[luvbach1]

Am I correct in remembering that no school shooter has yet breached a locked door?

If you are correct, part of the reason is that the shooter doesn't want to be waste time breaching a door; he wants to move on to easier targets.

[gundog]

I guess locking doors is just to complex a solution. Or maybe it’s just not inclusive enough. Just locking the bad guy out could be the delaying factor that gets them killed before they can do grave harm.