What if 2 other students - on opposite sides of the room - begin to shoot at the perpetrator? What are the rules of engagement there?
Better yet, what if 100 other students pulled out their guns and began shooting at the same time?
In this situation, you had one man in black emerge onto the stage and waste the teaching assistant.
At this point, armed citizens in the class would have opened fire upon the easy target, 20 feet in front of them on the stage. There would have been minimal add'l civilian damage - he was an isolated, elevated target with clear line of sight.
He would have been hit before he had the ability to shoot 16 more people.
You can always think of 20 scenarios where more guns in the situation *could* be worse. But in reality, most shootings are only stopped when the shooter decides to end it. Remember Va Tech? 30+ kids killed, double that wounded, because the kid just walked room to room wasting everyone. In that situation, an armed teacher or student could have saved dozens of lives. You have seen the youtube cell pics - the cops were outside talking about a plan while shots peppered in the background, kids dying.
On a side note, there was a daycare shooting in Cape Coral shooting about 2 weeks back (i'm in estero, about 20 miles away). A man walked in and took his wife hostage, babbled to her for 10 minutes, then shot her in front of the children. Well, a cop was on the scene in about 3 minutes, but he didn't have good info, and ended up shooting out the tires of a fleeing parent. After doing so, he heard the fatal gunshots inside. Then, he sat outside while the woman bled to death, waiting for his backup team and a plan.
So even on the scene immediately, police usually don't save the day. They clean it up. You're on your own, at the mercy or luck, or the gunman running out of bullets. I'd rather risk being hit by a stray from ten heroes in the room, than be at the mercy of Officer Slowpoke making his plan or shooting tires on the wrong vehicles.
