I was reading the thread about someone drawing on a guy that he ran down after a hit and run.
The general concensus was "don't get involved if you are not in danger or someone else is not in danger".
Lets say that you encounter someone beating up someone else with there fists. You think this guy might kill this other guy. No one is armed. It is a fist fight. What do you do?
Lets say you say "Hey quit hitting that guy, you could kill him" and the guy tells you "that is what he is trying to do"
Do you get involved any further?