I fell into a wiki-hole one night and for some reason was reading about cave diving and ultra deep diving. One of the things I thought eerie was that one of the divers tied the oxygen rope around himself after running low, so that no one would die looking for him, they could just bring him up. Thinking about that, and what goes through ones mind when faced with their own demise, gives me the willies.
It also talked about how people turn into a wax like substance when they have bene down there for long periods of time, like years. I also read about guys who died just trying to fish peoples bodies out of the caves etc. Crazy shit.