Just a few of my ideas---1) Bullet proof doors with bullet proof glass, Isn't the official Presidential vehicle protected with such?
2) Trained, armed security- retired Vets. 3) Teachers have too much responsibility as is, let the teachers teach! 4) Metal detectors at exit/entrance exterior doors. 5) Buzzer system at the entrance/exit exterior doors(my moms nursing home had this) doors are in lock down--No free access.