I'm all for arming teachers...if they are willing to train train train. Unfortunately, most "gun owners" are still working on the first two boxes of ammo they purchased with their firearm.
We gave what was supposed to be a 2 1/2-3 hour seminar on responding to an active shooter, that was pared down to 45 minutes with less than half the staff. Anything remotely related to a violent act against an(some) agressor(s) wasn't to be discussed. That left us with "awareness training".
Pay attention, watch the cues, the mood changes, pay attention to the kids and their adults. Report it "We can't do that, as it is a violation of district policies and opens us up for liability."
"Well, whatever your policies may be, you had best get it through your proper channels or you may be dealing with an event similar to what we are going to talk about next...actual past incidents."
That certainly wasn't the rainbow unicorns and bubblegum farts they wanted to talk about. Stockton, California; Jonesboro, Arkansas; Columbine in Colorado, and Virginia Tech.
Most teachers don't want to hear it ("Lalalalalalalalalalala"), let alone prepare for it.
After ranting to a friend I grew up with about this, who was raised to shoot and is now a teacher, she was surprised they let us speak at all, let alone for 45 minutes.
SROs and the Israeli method...armed parents with a vested interest in stopping attacks.