Here's a story about a teacher who died after breaking up a fight. It's not clear whether or not the fight was a direct cause. Nonetheless, the result is the same.
As a fairly new teacher, I came up the stairs one day to find two girls fighting. One girl appeared about to kill the other. She was smaller, but on top of a larger girl. When I came up she was alternately striking her and extracting clumps of hair from the larger girl's head. I wasn't sure whether the girl on the bottom was even going to have a head much longer.
I got called into the principal's office. The principal introduced himself for the third or fourth time, and told me how he liked to meet the new teachers, for the third or fourth time. He then explained that I should never get involved in a fight between students. If I got hurt, he said, my health insurance wouldn't cover me. I took him at his word and didn't get in between any more scuffles between students.
It seemed to me I was doing the right thing by not letting that girl get killed. But what do I know?