don't make dumb moves when you have a gun pointed at you.
Natural selection.
as to the legal matters, if you have a reasonable suspicion, (being on call that a dumbass was firing a pallet gun out the window), and he reaches for his waistband, it's time to POP HIM AND DROP HIM
I was a juror on a case similar to this back in 1987 in Miami.
48 year old man (African American) owned a used car lot in Liberty City.
20 year old man (also African American) drives into the lot, screaming and demanding money from the owner.
Owner tells him to get off his property while holding a gun pointed at him.
Guy (empty handed) keeps coming at him, flailing his arms and hands, cursing at him, telling him he's going to kill him.
Guy at one point flails his arm around behind his back.
Owner fires once, killing him.
Owner calls cops, trial ensues.
We all found the owner not guilty after deliberating for about 2 hours.