[metmom]

But how do you get to them and raise them up?

And can they be raised up fast enough to save their lives before their oxygen runs out without killing them with the bends?

[Salvavida]

Bends won’t be a factor because the ambient pressure is the same inside as it is on the surface, so nitrogen build-up in the bloodstream doesn’t happen.

The same reason submariners don’t have to worry about it, but divers certainly do.

[Equine1952]

I don’t think they are subject to high pressure inside the vessel. The bends are due to dissolved gas, nitrogen and others coming out of solution in the bloodstream during decompression during the surfacing. A decompression chamber drives the gas back into the bloodstream and slowly pressure is dropped to allow time for the lungs to get rid of the gases. Any scuba certified diver knows the procedure. Dives below 100’ are not for sport divers. The deeper the dive the greater the risk for any underwater endeavor.

[Jotmo]

They’re in a submarine that is kept at atmospheric pressure.

There are no “bends”.