[lefteye]

Crimes committed before the good guy drew his weapon were not prevented. After the good guy drew his weapon he prevented an armed robbery (at a minimum) and perhaps one or more homicides. When I think about it, this may be true of all (or nearly all) lawful and successful self-defense uses of a firearm, i.e., the facts that make the self-defense use of a firearm lawful always (or nearly always) require an unlawful act by the bad guy.