tonight on "nightline," proof of heaven? a brain surgeon believed close encounters with the afterlife were impossible until his own brush with death convinced him heaven is real. a shocking security breach of a multimillion dollar system protecting one of the nation's busiest airports. an abc news exclusive with the stranded jet skier who strolled undetected across airport grounds even though he wanted to be caught. and a second opinion. it was the assignment i thought saved my life. >> the unfortunate truth is you do have some heart disease. >> but the expensive tests this famous doctor gave me ignited a widespread backlash and tonight i ask him to defend his diagnosis.

good evening. i'm bill weir. here's a question, do you believe in heaven? various polls find that somewhere around 80% of americans do. but a harvard-trained brain surgeon wasn't so sure until he spent a week in a coma and came out with an incredible description of the afterlife. my co-an chore terry moran has the story. >> reporter: a mild afternoon in lynchburg, virginia and eben and holly alexander are at a high school soccer camp cheering on their son. they are a perfectly ordinary family with an extraordinary story. they have been touched by a medical miracle and maybe more. >> i mean, it was impossible after impossible after impossible. >> reporter: eben alexander, a harvard-trained neurosurgeon who

was a skeptic when came to religion survived a near-death experience and he now carries the memory of what he says was a journey to heaven. a journey that all his scientific training cannot explain. on november 10th, 2008 eben awoke with a searing headache. when his wife holly checked in on him he was having a tremendous seizure. >> i said, say something. he didn't say anything so i called 911. >> reporter: eben was rushed to the hospital. >> the only word woe could truly make out was help and the rest of his verbalization was purely screaming. >> reporter: he had been stricken with an extremely rare and virulent e. coli meningitis infection that was raf rajjing his brain plunging him into a coma. >> i mean, i was trying to die. >> reporter: in fact, doctors gave him almost no chance to live and told his family if he did survive he'd be brain damaged for the rest of his life. >> his eyes were just off and

cocked. just like no one was there. >> reporter: eben believes holly is right. he wasn't there. did you go to heaven? >> yes. in every sense of the word that's what my -- what my experience showed me. >> reporter: his first recollection, he says, was being a speck of pure awareness in a dark and murky underworld. >> and then i was rescued by this beautiful spinning white light that had a melody, indescribably beautiful melody with it that opened up into a bright valley, just an incredible rich ultra real world of indescribable complexity. >> reporter: god was there, he says, and he encountered him through an orb of brilliant light. he soared on the wing of a butterfly with a beautiful young woman as his companion and the young woman gave him a message to take back from heaven. >> you are loved.

you are cherished. there's nothing you have to fear. there's nothing you can do wrong. >> reporter: it's a beautiful vision, but heaven? a lot of people are going to say, doctor, it was a hallucination. your brain got zapped by this disease, all the wires got crossed and you saw a girl on a butterfly wing and you were spinning up in a melody. >> i know this was not a hallucination, not air dream, not what we call a confabulation and i know it occurred outside my brain. >> reporter: but how? how can he even suggest that much less claim it's proof of heaven as he called his new book. he showed us his brain scan. >> it wasn't leaving any part of my -- of it unaffected. >> reporter: your conclusion is because all of this outer area which is the higher functioning was covered with the infection,

what you experienced in the coma wasn't part of the brain? >> right. >> reporter: many neu neuroscientists are deeply skeptical arguing his brain must have produced his vision somehow most likely as he came out of coma but something else happened. after he recovered, eben who was adopted saw a picture of his sister from his biological family who died years ago, a woman he never knew. >> i knew who my guardian angel was on the butterfly wing. it was the most profound experience i've ever had in this life. >> reporter: your sister by birth and from a family that you didn't know because you were adopted who died several years ago who you had never met, you saw while you were in coma? >> yes. and that was the key. that explained everything.

>> that's for sure. >> reporter: dinnertime at the alexander home. >> jesus, bless these -- >> reporter: they were not a particularly religious family before eben's coma. he was a skeptic. not anymore. >> this proves that our soul, our consciousness, our spirit doesn't depend on the existence of the brain and body at all, and easily is actually freed up to a much higher state of knowing when it's freed from this body. >> thanks to terry moran. coming up next how the multimillion dollar security system at one of america's busiest airports missed a guy desperately trying to be found. the jet skier in jfk, next. [ engine revving ] ♪

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even what we all go through at the tsa checkpoint you have to wonder how is it a lost jet skier in swim trunking and life jacket could penetrate the runways of one of the busiest airports in the nation? it's an incredible story of lapse security and only abc's jim avila has it. >> reporter: daniel casillo lost in his prize jet ski exposed a multimillion dollar system at new york's jfk and he wasn't even trying. >> the whole intention was to be seen because you're in the airport. there's not to be some type of security. they have motion detectors. >> reporter: afc an unintended test of all those things, even the airport barbed wire, chain

link eight-foot perimeter fence that he easily climbed in his shorts and life vest. that was easy? >> there was no challenge at all. >> reporter: how did this young man become both a trespassing pain in the new york authority's neck and unofficial security consultant for one of america's largest airports? it started on an august night in jamaica bay off the shoreline runways of jfk. >> the jet ski just shut off. i looked around. no lights. no boats, nothing. no noise, just pitch black. >> he's miles away from the shore in choppy water but heads toward faint lights in the distance swimming behind the dead water craft pushing it towards land. it takes hours. >> the actual tower as you can see that was my landmark, the only thing lit up i could go to. >> reporter: finally reaching it hoping just being that close to the airport would set off alarms and lead to rescue. >> i expected maybe a helicopter. maybe a boat, something.

nothing happened. >> reporter: nobody patrolling -- >> i had nothing, nothing at all. i made a decision i'll have to get found. i'll have to take it upon myself to get over this fence to get seen. something's got to happen. >> reporter: now you're inside the perimeter of the airport. >> yeah, unfortunately, i was in the airport. >> reporter: no alarms go off. >> nothing. >> reporter: so danny keeps walking towards the tower, crossing, he says, at least one active runway and taxiway. >> i walked right across it without any type of problem. i didn't get seen. >> reporter: in fact his journey only ended horrifyingly enough when he reached the delta terminal 3 passenger terminal where he turned himself in to a baggage handler. >> i had to walk up to a cargo walker. that's jfk international airport. i walked to the terminal. that's crazy. >> reporter: america's airports are not as secure as the public may think. from rogue pilots climbing the fence at st. george, utah and driving a jet into the terminal or this 2010 wild ride at

dallas' love field. >> tower, what's the protocol? >> reporter: clearly many experts say the jaw-dropper at jfk signals something must be done. >> it's time to relook at perimeter security. these are early warning signs, and what the bad operators are out there doing are they're studying, and that's what bad guys spend their time doing. they spend their timeopponent. >> reporter: he got no rewards. charged with felony trespassing ultimately reduced to a misdemeanor violation. he now threatens to threaten the port authority for what he calls harsh treatment. >> you would think someone that went through what i went through would get medical attention, a cup of water, something. i got nothing. >> reporter: he never told prosecutors he was mistreated and he wasn't. in a statement they claim he was offered medical treatment and will fight what he says are his false claims. danny believes he deserves better. >> this is a major topic.

this is a big deal. i didn't mean to do this. but i exposed something really important and that's a flawed security. >> reporter: the port authority and raytheon say they are being corrected and increased patrols and working to make sure someone more serious than a lost jet skier never walks across runways at the jfk terminal again. for "nightline," i'm jim avila in new york. >> our thanks to jim. just ahead, it was the assignment that saved my life or so i thought until a second, third and fourth opinion and tonight, i'll challenge one famous doctor to defend his methods and diagnosis next. [ male announcer ] this is karen and jeremiah. they don't know it yet, but they're gonna fall in love, get married, have a couple of kids, [ children laughing ] move to the country, and live a long, happy life together where they almost never fight about money. [ dog barks ] because right after they get married, they'll find some retirement people who are paid on salary, not commission. they'll get straightforward guidance

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if you are a "nightline" regular, you might recall a certain story i did about a famous doctor and his belief that medical technology could

help end illness as we know it. after volunteering to sample his cutting-edge test i was stunned when he told me i had the kind of heart disease that could kill me soon. i walked away convinced that this random assignment saved my life but ten months later i heard from a number of doctors who aren't so sure so tonight a re-evaluation and a trip into the confusing and expensive world that too many american patients know all too well. all right. >> bill, have a seat. >> the moment of truth, yeah. >> that is part of you. >> the moment that shook me to the core happened on a sunny beverly hills morning in january. >> the unfortunate truth is you do have some heart disease now. >> first thought, i actually flashed to an image of my kid spreading ashes on the same mountain where i buried my dad. second thought, i deserved this.

>> whoo-hoo! >> for my first four decades i carried a secret arrogant hunch that i was bulletproof. sure, i exercise but i can't remember my last checkup. i don't even have a doctor and, yeah, i like salad but my food pyramid is built mostly with racks of ribs and a six-track and now after a ride in a full body ct scanner i had dr. david agus circling spots on a screen and describing the price of all that willful ignorance. >> these lesions and significant arteries in the heart can cause heart attacks in the near term so we all hear -- read in the paper about the 45-year-old who went jogging and died of a heart attack. these are the things we worry about. >> reporter: since he was described as a rock star of medicine and doctor to lance armstrong, ted kennedy and steve jobs i took his words to heart and started eating better. but then i heard from other well respected doctors that believe

that life-saving moment was just bad 34edz. >> when i saw that piece and saw that interaction, i'd say it broke my heart. the idea that someone would say to you based on that that you could drop dead from a heart attack, there's just nothing to support that. >> reporter: in the new paperback of his megabest-seller "the end of illness," he uses me and answers his critics. >> i'm a little shocked by the push-back i got positive and negative but it truly is an honor people are talking. >> my education came in the controversy over the ct body scan. >> yes. >> looking back, do you believe that test saved my life? >> i believe that test put an intervention in your lace where you changed you your behavior and what you're doing so there's a good potential it saved your life. >> the experts in cardiology i talk to say it's just not the data to support. >> reporter: my colleague

richard besser is the former acting head for the centers for december control and is in the camp that believes that expensive tests that found plaque in my heart can do more harm than good. aside from radiation, the results are often confusing or misleading that could lead to more expensive and risky tests which is why the american heart association and fda would never recommend this test for someone without symptoms. someone like me. >> it changed your behavior but you're in preventive mode and there's a major power to that. >> it did and i'm wrestling with whether my cholesterol score on a piece of paper or a good, wise chat with a doctor i trust would have had the same impact but the more research i've done, i mean, according to "new england journal of medicine" came out talking about calcium score, high risk is 300, low risk is anything below 100. mine was less than 50. >> right, but anybody with greater than 10 has an

eight-fold chance compared to the average of a cardiovascular disease. >> there are people with a zero score that die. >> no question about it. >> and people who live to 100 and have plenty of plaque buildup. it's not cut and dried. that's what you have, you will die if you don't change. a cynic would say you're using me to sell that book. i don't believe that. i think you believe what you believe but how do i get such different diagnoses from different doctors. >> you didn't fit the standard risk criteria. that being said i think the risk criteria must be wrong because you had heart disease. most 40-year-olds don't have it. you did. you can argue the technology and means to do it but we've picked up something that could save your life. >> this whole episode demonstrates the constant tug-of-war within medicine, one side determined to drive patients to the latest technologies, another taking a more cautious approach until decades of data makes sense of it all.

what worries me is that our story did more harm than good for the general public. and i have a lot of doctors who tell me that's the case. >> you know, the good is can that i agree with you, it created discord but i've gotten thousands of e-mails from doctors that supported it also including some of the leadership at the american heart association. >> no one argues with the core wisdom of agus' book which is eat fresh food, get plenty of sleep. move throughout the dare and learn as much as you can about your family health history, all of them commonsense steps that do not require a $1300 radioactive doughnut ride. >> so many of the things in his book are on target, but it is incredibly confusing because you're going to hear different opinions from different doctors and what people want is the truth and the truth is kind a moving target. >> by the way, dr. agus tells me all profits from the "the end of illness" will be donated to medical research. thank you for watching abc news. "gma" has a s