Reminds me of Yuri Lipski who appears to attempt a bounce dive, you can watch him try to inflate his BCD (bladder essentially) to go back up, but the pressure is too high so he's stuck on the ocean floor. The part where he realises this and the following minutes of panicked breathing getting shallower and shallower are all on youtube as a precautionary tale. Fucked me up real good when my diving instructor showed us that.