Quoted:
OK, I think I'm understanding it now.  There is no safety valve, no mechanism whatsoever, and when the pumps are turned off, the body is fully subjected to the water pressure at depth, connected to sea level pressure through the hose that no longer has a pump maintaining pressure.  If it weren't for that hose, everything would be fine for the diver (except he'd run out of air), but since it's connected to the surface with no safetly valves, the person at depth is suddenly exposed to sea level pressure?

OK, I admit I was wrong.  Not in science, but in understanding the mechanics of the suit and hose assembly.  I learned something today, both about deep sea diving apparatus and in hubris, I guess?  I made assumptions based on my knowledge, that, while they were "correct," blinded me to reaching a more basic understanding of what was actually going on.

A lesson in hubris is healthy.  Not fun, but critical to growth.  I apologize to anyone I talked down to, and for acting so smart and condescending when I was missing a critical piece of information that made me wrong.

Quoted:
Greenhorn, I think what your missing is that if the divers compressor AND check valve fails, the hardline supplying his air opens to ambient AT THE SURFACE. This means everything inside the suit is going to flow towards the lower pressure, air/flesh/etc. So, instead of the suit remaining at 150ish psi, it’s being squeezed by 150psi minus 14.7 psi. Thus, things become ugly for everyone and fatal for the poor soul in the suit.

Quoted:
My team at work responds to Delta-P diving accidents. I've seen fully suited divers (with their air tanks) sucked through an 8" pipe. Once you've seen that in-person, you really respect pressure