Okay setting aside whether there should be guns in schools, this argument doesn't make sense. There were, in fact, good guys with guns on the scene. The police prevented them from intervening.
As they should. You don't want to add random gun owners adding chaos to such a scene.
But this could have been prevented by police actually doing the job they were paid for. If they had taken care of the shooter like they should have, the question of other people wanting to enter to do the police' job would never have arisen.
Huh? I mean if they did their job there would be no need for that, but if not the least they could've done is not to stop people who wanna do something.