Your example isn't quite as cut-and-dry because in a lot of cases that's going to involve the Castle Doctrine as well, and "starts shooting" means there is an actual danger merely than a perceived potential danger.

Counter-example: You're walking on the streets, at night, in the "bad part" of town. Someone walks towards you with their hands in their pockets, and their head covered with a hoodie. They say "Hey, what are you doing here?". You perceive this to be a threatening situation and fear for your life. Are you supposed to: a) pull out your gun and shoot them, or b) run away?

Some proponents of Stand Your Ground would say that option A is perfectly fine, some proponents of Duty To Retreat would say that you must attempt option B first, and fall back to option A only as a last resort.