I'm reading a very good novel, called "Smilla's sense of snow". A minor figure tells this story from the time he was a frogman with the marines:
Going down, I glide through a cold belt [...] I panic. I lose my safety rope. [...] They told me later that Føjl saw it. And took a lead belt in the hand and jumped into the water without bottles. Only a rope in the hand. Because he couldn't waste any time. He dives to me. He catches me at a depth of twelve meters. But he's diving in a dry suit. It means that the water pressure presses the rubber against the skin. Every ten meters, the pressure rises by one atmosphere. At ten meters, the rubber edge cuts at the joints and knuckles through the skin. All I remember are clouds of blood.
I have never dived, but I've worn a dry suit, and can't imagine this happening. Even if the construction used to be different - the story must be happening sometime in the 1970s - what would the use be of a suit which hurts you at 10 meters? Why would people dive in them? So the story sounds like an implausible melodramatic plot device. On the other hand, the book seems to be correct at its other plot devices (I hadn't heard of Guinea worms before, but they are as shocking as described in it), so maybe this story is possible after all.
It would be too subjective to speculate about the likelihood of somebody trying this heroic saving and succeeding. But the "your suit cuts your wrists" part should be easier to judge. So, is (or was) this a real danger? If yes, how do divers avoid it when diving under more controlled circumstances?