Simple solution for classroom doors?

[kevin9]

Rather than searching for ways to turn schools and other public places into jails or impenetrable fortresses, we should be looking at ways to make these places less desirable for those who want to use them for satisfying their sick minds.

I would suggest that improving defensive security* at schools and colleges need not be oppressive, and most certainly is not mutually exclusive with increasing offensive security* by allowing concealed carry.

* "defensive security" = contain and isolate threats, "offensive security" = capable of taking action to end threats