tonight on "nightline," hospital horror. shocking news from baltimore today, where a man shoots a surgeon and then kills his mother and himself, raising alarming questions about security at our nation's hospitals. we've got the latest from johns hopkins. under the sea. they can grow to be as big as a bus. whale sharks. more gentle whale their ferocious shark, though. we go underwater for a close encounter with them. plus, wet and wild. they're the hottest parties in las vegas. the sun, the suits, the tunes and the booze draw thousands every day. it's a huge new business for hotels, and it's a "sign of the times." >> announcer: from the global resources of abc news, with terry moran, cynthia mcfadden, and bill weir in new york city, this is "nightline," september 16th, 2010.

>> good evening, i'm terry moran. and we're going to begin tonight with an astounding and deadly confrontation in a baltimore hospital corridor, where a man upset by his mother's grim prognosis shot the attending doctor, and then killed his mother and himself. and, in a strange twist, this shooting bore an eerie similarity to a "grey's anatomy" episode that aired tonight, meeting fiction in just a horrible way here. in baltimore, authorities are still piecing together just what happened in that hospital, and john donvan has our report. >> situation is far from over. as you can see, just an incredible scene. >> reporter: it was one of those, oh, no, not there situations today. a hospital building, suddenly flashing across the news channels. >> certainly, a scary situation for patients, anyone visiting patients and obviously for hospital personnel, as well. >> reporter: the report, a man with a gun inside. >> security officers are on the scene, baltimore city police are

on the scene. and we are just waiting for additional word about what's happening. >> reporter: and what is worse, he had apparently already used it. >> baltimore. that's where police say a doctor has been shot at johns hopkins hospital. >> reporter: this was the scene for several hours today at johns hopkins in baltimore. >> kind of really chaotic. nobody knows what's going on, as far as what the situation was. >> reporter: but now, word was coming out that a doctor had been shot. >> can you tell us about what kind of doctor he is? >> oh, excellent doctor. very humorous and a nice fella. >> reporter: yet the gunman was still in there. >> it's scary, just knowing that someone is on the outside, on a rampage. >> scary and, like totally unexpect unexpected. you come to the hospital for help and find out somebody is in there shooting, like, it totally puts you, make you think, what is really going on? >> reporter: and then, police began releasing details about what had transpired in there, involved a man named paul

pardus. >> during the course of the situation with the doctor mr. davis removed a small semiautomatic handgun from his waist area, waistband area and fired a single gunshot that struck the doctor in the lower chest, upper abdomen. >> reporter: the doctor, david cohen, a surgeon, survived and is now in stable condition after emergency surgery. he reportedly had operated on pardus' mother and had been delivering news that she was not doing well. that is when pardus shot him. after which, on that eighth floor, he went into his mother's room and killed her. she wasle 84. and then he killed himself. >> very troubled earlier today to learn on the rinse dent here at johns hopkins. johns hopkins is a very proud baltimore institution. >> reporter: and that oh, no, not there, thought, it's partly

that hop kips skins is such a show case of a hospital. 30,000 people there. it's a national leader in medical research and treatment. >> you know where i can find the chief of surgery? >> reporter: and yet, only tonight, the startling coincidence on television, in a fictional hospital -- >> he's on the floor. >> who? >> the shooter. >> a shooter? there's a shooter in the hospital? >> my god. >> reporter: something not that far off today's true events. on "grey's anatomy," a man blaming a doctor for giving poor care to someone he loved did this. >> shut up. no talking. you're not the man here. i'm the man. >> reporter: but what happened here at hopkins today, somebody with a gun in a hospital, it's not even the first time this year that that has happened and i'm not just talking about tv shows and movies. let's start with what happened in march. connecticut, in march. and 85-year-old man shot a nurse

and then he was shot. april, knoxville, a man thought a doctor implanted a chip in his body shot three people, killing two of them, then he killed himself. july, mayfield heights, ohio a man shot and killed his wife. she was a patient. then he killed eded himself. august, las vegas, another husband and wife murder suicide, only this time, the wife had the gun. and as we already heard her say outside hopkins today -- >> just knowing that someone's on the outside, on a rampage with a gun. in a hospital. where we're supposed to be protected. >> reporter: yet, it's not all that obvious how to stop a gun from getting into a hospital. any more than into a church or ball game or anywhere we've chosen not to live behind metal detectors. though one expert said tonight, maybe doing that is appropriate at times. >> i would say that if we did our own risk assessment, we felt it was a high risk we would consider it. >> reporter: but the kind of violence that happened today, that could happen anywhere. >> we ain't safe nowhere.

we ain't safe nowhere. >> someone shot a doctor. >> a doctor. surgeon. a surgeon. >> reporter: and the only glimpse we have into what drove paul pardus, it came tonight from his brother. >> he was saying that -- that she may not be able to walk again. >> was he really close to his mother? was he really close to your mother? >> yeah, he tried to be with us and to do as much as he could. >> reporter: now, they are both gone. two deaths, hard to take even in a place where death is part of every day life. i'm john donvan for "nightline" in baltimore. >> so mayhem came to johns hopkins today. "good morning america" will have the latest on this story. thanks to john donvan for that. up next, we're going to shift gears. we'll take you into the animal kingdom, and these gentle giants. they're among the biggest beasts in the sea. tonight, we swim with the fishes.

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and and we're going to turn now to one of the most mysterious creatures of the animal kingdom. jacques cousteau himself is said to have seen only two. they're giant sharks. much bigger than great whites. but this shark is far from jaws. they're whale sharks, and, in fact, they are gentle giants, though it's still plenty exciting to see one up close. just ask my co-anchor bill weir as he discovered for our series, "into the wild."

>> reporter: for centuries fishermen on this gorgeous island would come to a church made of coral and pray for protection from the biggest beast in the sea. the low cams in these village ss are talking about the wheel shark. one of the most ancient and mysterious creatures on the planet. glassy seas. perfect day to mingle with sharks. >> if we see whale sharks we interact with as many as we can. >> reporter: this is the boat of choice in the philippines. and this one takes us past a smoldering volcano. into a bay where the allure of the giant fish has created a new vocation. the whale shark interaction officer. >> because this boat has no propeller guard and then it is very dangerous. >> reporter: how fast will the whale shark move? >> actually, they do not swim very faster. they swim very slowly. >> reporter: as we bounce across

the waves, spotters perch on a cross staff, laser focused on the water. waiting for the tell-tale shadow. and when it comes, there is sudden urgent action. all right, we got a shark! we flipper after our guide waiting for the signal. >> ready? >> reporter: i plunge eyes wide, peering, heart pounding until suddenly -- there it is. out of the blue green murk comes a behemoth with 3,000 teeth and at least that many tell-tale spots sprinkled across his massive back. as quickly as rearrived, he disappears into the deep. wow! he's huge. it's the size of a city bus! and i was too excited to go down. i couldn't hold my breathe to get after him. oh, that was cool. we climb back onto the boat to hunt for another, and this is

probably the part when you're wondering, what kind of suicidal moron snoshg ms with sharks? yeah, sorry about the melodrama. i probably should have mentioned that these are gentle giants. and each of those 3,000 teeth? about the size of a grain of rice. despite the scary name and size, they are more whale than shark. grazing on a diet of plankton and shrimp larva. even without the threat of being eaten, there is something exhilarating about being this close to a creature this big. are you kidding me? oh, my god. man. that was unbelievable. how big was that? >> 25 feet long. >> reporter: 25 feet long. wow. our morning is filled with nearly a dozen whale shark encounters, which would have

been inconceivable a couple of decades ago. >> second whale shark in just a couple of minutes and even the great scuba diving explorer jacques cousteau only saw two in his life. >> reporter: they have been swimming the earth's oceans for 50 million years, but so little is known about these creatures. they live to be about 100. don't start breeding until age 30. an act that has never been witnessed. in fact, the first baby ever recorded was found just this summer here, and is considered a huge breakthrough in understanding. >> studying a highly migratory spee seeps is very difficult. because you need to actually track them which is nearly impossible. >> reporter: and as experts tag, tourists gawk. according to the world wildlife fund this is one of the most successful marriages of tourism and conservation anywhere. these $25 encounter cruises have

given a giant boost to the local economy. and the fishermen whose forefathers prayed for protection from the whale sharks now pray for the whale shark. poachers, willing to break the law, can sell one for around $5,000 on the black market. that's two years' salary in this part of the world. so, you can imagine how hard it is convincing local fishermen that these things are more valuable alive than dead. we saw a different kind of ocean stress, on our journey through the south china sea. coral reefs, once dynamited for fish, are slowly recovering. among marine sanctuaries with scarce enforcement. and we spent 24 hours with men who make a living catching tuna in the most primitive fashion. hand lines and squadid bait. but they didn't get a single nibble. hard to compete with giant industry trollers in these overfished waters. but back in the water the whale

sharks are providing a small economic bright spot. the challenge now? managing the success. >> among the biggest threats would be the very success of the program. too many boats, too many tourists going in during the season, might effect the long-term behavior of the animals. >> reporter: but their interest is what could sustain them. >> exactly. >> reporter: how do you balance that? >> well, it is always better to be loved, not nearly to death, rather than being slaughtered for food or fins. >> reporter: i look up and it's coming right at me. it was, the big gaping mouth, little beady eyes. i thought he was going to hover me right into his gullet. a living creature the size of this boat just chilling cruising. wow. that was great. >> that was cool. bill weir there swimming with some very big fishes.

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>> announcer: "nightline" continues from new york city with terry moran. >> certain human discoveries electricity or plastic, say, are so central it is difficult to imagine life without them. well, after you watch our next report, you may agree it is no great exaggeration to say las vegas has experienced a recent breakthrough of just such proportions.o0 owens this is a "sign of the times." >> reporter: it's never been tough to find a good party in sin city. but these days, the biggest one happens to be at 2:00 on a sunday afternoon. every sabbath, thousands flock to the pool at the hard rock hotel and casino in las vegas for a day-long party called

rehab. >> night life ain't nothing. >> reporter: really? >> all about the pool party. >> all about the pool party. we pop four bottles. >> the pool is where the spot is. beautiful tans, beautiful people, music. >> reporter: on a typical sunday, rehab draws nearly 4,000 people. you know a party is pop crew lar when it gets its own reality show and rehab has one, on tru tv. >> that's a perfect storm. >> reporter: if imitation is the sincerest form of flattery, rehab must be feeling pretty good these days. >> if you don't have a pool, you're not going to be relevant. >> reporter: here in the middle of the desert, where 120 degrees is as common place as the slot machine, the party has suddenly moved outdoors. during the hottest hours of the day. >> used to have people come out here and come for the night life.

in the day, there was nothing for them to do. people don't really want to come out here and gamble. the younger generations want to party. this gives them a place to go. >> reporter: and to spend. even in the sluggish economy, rehab's rev nugss are up 10% from last year. up a whopping 135% from just four years ago. >> the clubs are the clubs. but the pools are where everything is happening now. in the last two years it's changed because the hotels have dump millions of dollars into these pools. and when you look up at one pool that just opened, they spent $75 million on that pool. it's incredible. >> reporter: mark jay visited vegas for the night life. >> i spent ten minutes at the pool. >> reporter: that was ten years ago, now, he lives here, and this summer, he's producing five of vegas's biggest pool parties every week. >> great pool party is almost like baking a cake. you need different layers. and, you know, the most important layer is your sprinkling of pretty people. we have a team of people that go

out looking for the models, invite girls that we find in clubs. you need the day beds, the bottles. and the music is very important. which dj is playing. there's different layers to make it successful. >> reporter: you forgot drinks. >> people like to drink at these pools. sometimes a bit too much. >> reporter: we met mark at one of cesar's palaces eight pools. five of them new this year. the resort just finished a $60 million expansion of just its pools. >> nobody invests, you know, $70 million in a pool just to get small returns. when you see all these people checking in, especially in the demographics of 21 to 35, we know they're coming to our pooms and going to come here spending money on the day beds, the cabanas. all about driving revenue to the hotel. >> reporter: how much? you do the math. >> just to come into the best pool, almost $40 a person. just to get you in. you don't have anywhere to sit

or put your towel. if you want a day bed, you can be looking from $10,000 below. >> reporter: some of those cabanas may be nicer than your living room. once you have a place to lay your head, you'll need something to quench your thirst. how many of these can you handle in one day in temperatures like these? >> we go through 800, just basic mow here toes a day. the black drag, 3,000 a day. >> reporter: drink in hand, it's time to go swimming. that, too, comes with a twist. swim up black jack anyone? only in vegas can you gamble in a pool and under a water fall. if you're looking for a quieter scene, the options are dwindling. at the new hotel, the pool feels more like a spa. think fancy fruit popsicles and foot massages. but in vegas, this is the exception. this is increasingly the rule. from celebrity favorite wet republic at mgm grand to tao

beach at the venn knee shan. these megaresorts have placed their bets on the next generation of customers, and it's paying off big. >> this is what we came from, to relax, we thought, but -- >> that's why we came. >> the pool. >> reporter: so you're not here to gamble -- >> usually, yes. usually yes. inside, no. >> everybody is partying, you're in the water so much better than going to the clubs at night. >> suddenly, nighttime is for sleeping again? >> who would imagine? >> reporter: i'm ryan 0owens for "nightline," pool side in las vegas. >> what happens in vegas. thanks to the overdressed ryan owens for that report. and when we come back, newly minted senate candidate christine o'donnell on condoms. you have to hear this. but first, here's jimmy kimmel with what's coming up next. >> jimmy: thanks, terry. tonight, ben affleck is here, maura tierney is with us.

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