I'm sorry, can we back up to the OP for a second here? Did you really suggest shooting people who are near the guy mugging you, because A. they might possibly become a threat at some later point & B. to eliminate witnesses? Really?
I thought this board had a "don't suggest murdering people" rule but perhaps I am mistaken. I can only hope you're never involved in a self-defense shooting, as I've gotta think "Should I kill any witnesses, you know, just in case?" would sound just as bad to a jury trying to determine if you were reasonable in your actions as it does to me.