From the video it was clear the instigator of this situation was the younger man Chad. He was the one that got up from his seat to directly confront the old guy sitting in his chair for talking to management for his texting during the previews. He was the one that saying angry words at a senior citizen. He was the one that reached forward to take the popcorn away from the old man and throw it in the old man's face. This obviously wasn't his first outburst of uncontrolled anger in a public situation like this based on how his wife was trying to restrain her husband before he reached for the popcorn.
Chad, the younger man, would certainly not be dead right now if he didn't make a physically threatening motion and act out on his anger with intimidation in public. There is no disputing that.
As for Curtis's response to decide to shoot, I would have to hear more evidence from what was exactly expressed and said by Chad the moments leading up to when he decided to reach over and grab Curtis's popcorn. And the action he was doing after he threw the popcorn. He is a bit off camera so we are unable to see his actions after he throws the popcorn. If it looks like he is about to do more to follow up on that popcorn throw, then Curtis would have a justified assumption of further incoming and escalated violence that may be impending and can legally shoot in defense. Again, this is going to be a hard case for Curtis, because there is still a few seconds between when the popcorn hits his face and when he continues to extend his arm to aim his gun to fire. He is obviously making rapid decisions in that time frame to decide to continue his course of action of drawing his firearm, extending it, and pulling the trigger. The crux comes down to if it would be considered reasonable in his position at the time, given all the evidence, for a person of his age and capacities to consider determine if there was still enough of an imminent threat to legally shoot in self defense.
