Here's my story
We were doing some night dives in a location with some GIANT coral walls, well we tied up to the buoy, it was pitch black, no lights from anywhere but our boat, we were also diving with Nitrox, like a 34% O2 mix (we breathe 21% oxygen at sea level) and as some of you may know, Oxygen becomes toxic at a certain depth in water, you will have pretty much NO warning signs, and you basically have a seizure, and having a seizure underwater, breathing from a regulator that is easily spit out is really not a good thing.
Anywho, the reef is something like 50 feet below the boat, my buddy gets in the water, but goes down without me as the boat is drifting and he cant keep up with it or hold on to the back safely...
There's this chick that is there with her husband, no idea where the husband is at... So she jumps in the water and a few feet down her light dies or something, I jump in and descend about a minute after her... So I look down and I see, PRETTY FUCKING FAR DOWN, there is a FAINT green glow, and all the other divers have huge lights projecting 80 feet down, so I realize that this is that woman, without a light, in pitch black water. So I descend down there, and I'm trying to get her attention but NOTHING, I look at my dive computer and see were already 90feet down!!! I get down to her, GRAB her vest, inflate her enough that she stops sinking, and I show her my computer, 115ft! Then I pull the backup light I had on my vest, hand it to her, and give her the signal to surface, sure enough she does, and at this depth you cant even see the boats lights, you cant see the bottom either. Want to know why you couldnt see the bottom? Because the boat swung away from the reef about 60-70 feet from the actual coral wall... From what I know that wall descended down to the bottom, which was somewhere between 500-800 feet. The oxygen mix were using becomes toxic at something like 130 feet...
Anyway I ask her what happened and what she was doing, and she told me that she was waiting to hit the reef, which was at 50ft, and she couldn't tell how fast she was dropping or where she was.
So basically she would have probably had a seizure, drowned, and sunk to 500 feet. If she didn't have a seizure, she would have ran out of air in less than 5 minutes (you breathe MORE and MORE out of your tank with each breath the deeper you go, because the air is compressed a lot)
What a way to die huh? Thank fucking god for glow sticks.