They're thrill seekers. It's clear to me they've already anticipated death in advance and they know good and well how dangerous it is based on the things they say, if only just to push the limits and add one more day to life on earth. Hell, ocean ramsey may even be perfectly happy to die getting ripped up by a shark should the day come. This is just how serious thrill seekers are. Stupid? Sure. What would a human be if they weren't stupid and willing to flirt with death from time to time.