I told my boss that I'd quit on the spot if he insulted me again, and he insulted me again immediately. He tried to apologize and I ignored him. He later went out to his car and came back with a pistol, "joking" that he was so mad that he could kill someone in a fit of rage, which is a pretty obvious implied threat. He's in massive debt and trying to sell the business, which he can't do if I quit. He also lives down the street from me.
I know what I'm going to do, but what would you do?