[Eye of Unk]

Why not just build a kevlar lined safe room in each classroom? Or have several in position around the school, one way bulletproof glass and no way to gain access if its locked from within.

I can think of a way to build portable units of ballistic material that literally just snap together, ideally it would be something capable of taking multiple heavy hits from at least 30cal. When a shooters alarm is triggered in a school students go to the nearest ballistic shelter.

[Yosemitest]

Nothing protects people like a gun, and the first thing these stinking liberals do when they get in trouble is CALL A GUN TO THE SCENE OF THE CRIME.
Anyone who would restrict us with "gun control" should be banned from having ANY security service guard them, including the secret service.
Mandatory concealed-carry is the only answer.