You're walking out of the local mall at night after doing some late night Christmas shopping, and BG runs by and snatches your wife's purse. You are of course in Condition Orange, but it's a busy shopping mall, the BG isn't a teenage punk, but rather a middle-aged white guy with a polo shirt and khaki's. He has not presented a weapon, however you don't know what he has.
What do you do? Do you pull (your weapon) and pursue? Do you shoot him in the back (he is after all in the process of committing a felony robbery)?
Your wife's purse of course has cash and personally identifying information about where you live, etc.
(The assumption can be made you are in a "Stand Your Ground" state that allows you to act if a BG is "committing or about to commit" burglary/robbery in any degree)