I wish someone would report the entire timeline. I heard initially that the school had no resource officer, then I heard the resource officer confronted the youth outside, but was shot in the leg during the scuffle and at that time Ramos lost his bag of spare ammo. After that I can't imagine what happens, but it takes a while to get reinforcements,,, by then he is barricaded in a room.
I would think keeping civilians outside and out of the lines of fire is a must,,, they have to be able to tell the good guys from the bad guys and they already have to be concerned about hitting kids and teachers without cluttering up the place with parents.