Underwater gym

I dreamed I was sitting on the mat in the grappling gym; the mat was full red, and packed with people rolling. I was reading a history of martial arts, crosslegged in a corner. Finally I got tired and decided to plunge into training. One of my old training partners was there, a tall, bald fellow, so we rolled, very lightly. Neither of us were injured, and nobody clearly came out on top. The bell rang, signaling the end of the round. "You're good," he told me, but I shook my head in dismay, knowing that was not the case. Then I left the gym.

You had to leave via a submarine, as the gym was underwater. An old, creaking machine, something out of Jules Verne. I was in the submarine with my training partner's wife and the Charon-like pilot of the craft. As we surfaced, the wife cried out in horror, and we all turned to look out a large, fishbowl window. There was my training partner, or what remained of him. He apparently tried to swim out of the submerged gym, but there was a pin-sized hole in his arm, some sort of cut perhaps, and somehow the water pressure caused his body to implode. His limbs floated about, unrecognizable, amid a blood red cloud.

I looked down in dismay, and wondered: was it I who gave him that cut?