Well.... My guess would be that his ego got him.
I think this for 3 reasons.
1) To me it looks like his gear was functioning so I would bet that he meant to go all the way to the bottom. Holding the computer up to the head-camera to record the "proof" of the "accomplishment" cinched my thinking on this point.
2) After that something happens which, given the depth, might very well have been him toxing. In any case he clearly didn't get "entangled" in the sand. He was also not out of air and the regulator was clearly in his mouth based on teh sounds. Also if you listen to his breathing in the last few seconds it's much *much* slower than you would expect if he were in panic. Therefore I don't believe that we're seeing panic. And if it's not panic then I'm willing to put my money on toxing. That my logic on that.
3) IIRC he was Russian. With all due respect to individuals, Russians as a group are *notorious* for making stupid deep bounce dives. In Egypt people from Western Europe avoid diving with them if at all possible because of their penchant for dangerous 'stunts' like this. It's all macho, ego driven adrenaline junky stuff. Where I live people joke cynically that the French invented Scuba to keep the Russian population under control.
So that's my thinking. I think what we're seeing his is a dangerous stunt gone wrong. The way I see it, I would bet that this diver deliberately went to the bottom of the blue hole to set a personal record, took a moment to record the fact on his head camera before toxing out and dying.
R..
