A man who ran out of air at the bottom of the ocean

I'm signed up to be a cryonics patient when I die, but yeah, the chances are pretty much nil. Personally, I'll take a slightly diminished bank account and a potentially non-zero percent chance of further life over a zero percent chance, but I won't delude myself into thinking that there's effectively any chance of success here.

I think they had mixed results, and I haven't seen them or their competitors launch their products.

It works though, but it seems very difficult to cool the brain without chilling the whole body.

We were told that we could possibly make it 3 to 4 minutes at FL250 before having to go back onto oxygen. I managed to get to 5 minutes, but was was pretty much useless after the 3rd minute. I started to feel a real out of body experience, and it was like I was watching my own body do stuff but I couldn't really control it. I managed to get my own mask on and gangload the 3 switches, but I remember watching my colleagues in the chamber struggle and they had to be assisted by the RAAF team. The guys outside the chamber kept a hawk eye watch on all of us, and the guy in the chamber were quick to assist those of us who were in trouble.

What amazed me was as soon as we 'gangloaded' the switches to go back on full O2 with the masks on, recovery to full lucidity was super quick - within 1 or 2 seconds. It wasn't gradual, it was as if someone just whipped a heavy blanket off your brain!

Side story - before we went into the chamber, we had to be fitted for our helmets and masks, and I was seated in the 'fitting chair' in the crew room as 3 RAAF specialists slapped a bone dome and mask on me. Unbeknownst to them, that mask had just come back from a test facility, and thus it still had the wax seal on the end of the O2 hose to the mask.

Normally, there is no seal, so when the mask is clipped on during a test, you can still breathe normally as the valve at the open end just opens and shuts with your lung pressure. With the wax seal on it though, NO air gets through.

It was a few seconds of odd feeling when they snapped the mask on and I tried to breathe in but nothing happened. I remember feeling really freaked out at the sensation of wanting to breathe, but feeling and experiencing absolutely nothing. I started to grapple with the mask release, but they thought I was just uncomfortable with the fit and they kept slapping my hands away and adjusting the side straps.

I went into panic mode, and I am not sure what prompted me, but I started reeling in the trailing hose from my mask and lifted it up to see the seal on the end. One of the crew saw it and exclaimed before grabbing the hose and ripping the seal off. I gulped down lungfuls of air. Not the best start to my first chamber session!

There was a UUV in the water, which helped to locate the casualty but wasn't capable of performing a rescue.

Bailing out to open-circuit SCUBA doesn't help for very long, because of the immense pressures involved. As you go deeper, you need more pressure to inflate your lungs. A cylinder that lasts for an hour near the surface will only last for a couple of minutes at 100m. Tethered divers do carry bailout gas cylinders, but they're very much a temporary fix for brief losses of gas supply.

There are major logistical problems with portering dozens of gas cylinders to a job site that may actually increase the overall risk, because of the far greater time spent in the water. That pile of cylinders won't help you a jot if you lose the job site or you're incapacitated. Saturation divers are increasingly switching to closed-circuit rebreather bailout systems, which recirculate the breathing gas and so are far less affected by depth.

Even that is only a partial help because of the effects of hypothermia - if you lose your umbilical, you lose the warm water supply that stops you from freezing to death. You also lose your lighting and communications, which substantially impedes your ability to self-rescue.

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