Think it would be very hard to re-act quickly in that kind of situation. Many people would probably still be in a state of shock unless they had some kind of law enforcement or military training in a situation like the NIU and Virginia Tech killings.

Did not the old gunfighters get by on the fact that even though many people in the Old West wore guns few people were willing to shoot another human being? It would have been different in a military situation like on Little Round Top at Gettysburg but there you have your fellow soldiers with you.