What attack??? the popcorn attack??? he was all out of ammo??? he had no more popcorn to attack with.
Get a grip —
So you don't believe that throwing objects into someone's face is a criminal act?
Regardless of that, what was the popcorn thrower going to do next? That will definitely be discussed in any trial.
I've asked you to describe what a reasonable person in the situation of the ex-cop would expect to happen next.
Obviously you don't think anything threatening was going to happen. Tell me what you think the likely continuation of the situation would have been if the ex-cop had not drawn his gun.