A lot of factors would have to be considered. Just because somebody might have been carrying a firearm doesn't mean he/she would get involved. Or trained on how to react in that situation.
I agree. When you're talking about an active shooter situation such as this inside a very crowded movie theater, with every one running the same direction toward the shooter to get out, the possibility of missing and hitting someone innocent is extremely high. Also, someone bumping you and causing you to accidentally shoot another person is also extremely high. In addition, it's dark so you wouldn't be able to tell he is wearing full body armor including a helmet. Your best bet would be a face shot and you better be a really good shot under pressure and pumping adrenaline. Of course, ou wouldn't know about the armor unless you illuminated him with a light. Then, of course, you've attracted his attention.
Marty
