yep, we have to plan for it, also, ever since sandy hook.
the problem is that our classrooms weren't designed for anything remotely like this so there really aren't very good places to shelter. we also have doors made out of something just a notch above balsa wood, so if someone really wants to come it, the deadbolt isn't going to stop him. i've already run through a lot of nightmarish scenes in my head on steps i'll need to take to protect the kids, and none of them end terribly well for me. but i think i'm prepared to act when needed, and hoping like mad it'll never come down to that.