Quick question for those of you advocating carrying at places like a church. Say, for example, that the entire congregation felt the same as you and brought their gun to church. Further, let's assume that this guy was sitting in a pew when he stood up and started firing. You then get up and (understandably) try to take him out. Others in the congregation don't see what's going on as quickly and by the time they comprehend the situation, all they see is you and a bunch of other people shooting. Is this really a better situation? How are they supposed to know who is the "bad guy" and who are those trying to do the right thing? What if there are multiple "bad guys" intermixed among "good guys?" What if there are a bunch of innocent, unarmed people around the shooter--are you still going to be shooting at the guy?
My problem with the notion that more armed people equates to more safety is that scenarios like these are unlikely to be as simple as they are portrayed in which there is a clear "bad guy" who is taken out by one person who clearly understands what's going on and shoots an accurate shot in the midst of a crowded facility during what is, by definition, an incredibly traumatic and scary situation. Real life is much more nuanced.