ask you school district to beef up security zone and protocol
Add metal ditectors at entrances and auto lock down gates(bullet proof ideally). Ave. mass shooting time is 3 min., so to isolate the shooter is critical to gain time for police to come. In the mean time, the school can get all students into more secured rooms and lock down the whole school.
Our school district had this system for many yrs, and we are not in inner city.