martin: oh! that was fantastic. he came out upside-down. >> simon: we're right next to seal island here. population: 50,000. when you see a shark going for a seal, who are you rooting for? >> chris root for the seal. >> simon: chris fallows is a shark tourism operator. i think we can really relate to the situation of the seals, >> fallows: sure. >> simon: they're at home sitting in the sun, happy and safe and having a wonderful time and everything's great. but when they get hungry, they've got to go out into the sea, and in the sea, there are a lot of rough characters. >> fallows: yeah, it's a catch... catch 22. unfortunately for the seals, they need to go out and feed, and at this island, they've got a very good chance of being eaten by a white shark. >> simon: after watching a shark have a meal, a lot of tourists do the same, go back to shore. but some stick around, tempted to leave our world, if ever so briefly, and go down to theirs, underwater. it's the thing to do these days for seekers of adventure and adrenaline. you do it, of course, from the safety of a cage. safety? this happened to tourists not far from where we were. a shark actually got into the cage. if he hadn't