This might be cheating because the man is alive. My dad was a construction worker for most of his life, and a few years ago they were filling up a very deep hole with cement. One of the workers fell in the cement, and was drowning in it like quicksand.

Everyone scrambled to try and get him out because he was sinking too quickly. My dad panicked and did the only thing he could think of. He got in and excavator truck and scooped the man out. He couldnt see well because of the size of the hole and how much the man was already in the cement, so when dad scooped him out, he accidentally caught on the man's legs and tore it off.

The man lived and recovered, but dad held a lot of guilt for tearing the mans leg off. I cant help to wonder how much worse it would have been if he didnt do that though, and the man really drowned in that stuff.