Part of how I would handle it depends on the specific geography of the incident. Assuming my friend is in a position where they could realistically have been injured I am going to be asking them before, during, and after the 9-1-1 call if they are injured. I am not going to tell them anything, I am going to ask them things. Not about the bad guy or what he did, but about them. I am going to try to get them to knock their brain from freaked out feeling mode to thinking mode. Are they sure he didn't cut them? I am going to have them check themselves for any bleeding.