Situation #1: Well, unless I see a weapon I don't think pulling my own gun and firing would be justified.
Situation #2: Mugger flashes and threatens. The gunfight has already started. He just wasn't smart enough to draw and fire first. Hopefully a little misdirection (dropping my money) will buy a second or two for a clean draw. Then it's time to put my Hydro-Shoks to work in C.O.M.
God's creatures big and small, eat them one, eat them all.