It is not narcissism when someone jumps up three feet in front of you and displays violence as he is screaming at you. The event was over and done with until the guy who got shot decided to get physical and assumed a threatening posture and threw something in the shooters face. What has not been reported is what the guy was screaming. Was it a verbal threat or words that conveyed his ability to do violence?
I'm sorry this all happened it was needless. I'm very much not patting the shooter on the back either. It is clearly a fact that the guy who got shot did have a big part in what happened and made some bad choices. It was his choice to continue and escalate the confrontation after the old cop returned to his seat. I'm still going to wait and see how this all plays out in court.
Technically, I fall back on this: An armed society is a polite society.
Imagine if everyone in the theater had a sidearm and everyone knew it. It would go down much differently. No popcorn would have been thrown, for starters.