Complacency and False Security in Public Places - Mass Shootings

Why don't schools have better security

The Chemical Connection to Mass Shootings

Two things here.  We know that the desire to spend money on administrative staff is more important to school proponents that actual security.

We also know that many of the mass shooters have psychological issues and were either prescribed or on anti-depressant drugs or some other mind altering chemicals.  These drugs will make you act crazy if you don't have a problem so if you already have a problem with stability there is no telling what kind of outcome you'll get.