I assume it/they will be located in the admin offices — probably under a locked cover to prevent accidental pushes.
[enter armed invader]
[Admin Barney Fife approaches, challenges, gets taken hostage.]
Witness: We have an armed invader. Someone push the panic button.
Admin aide: Okay, who has the key to unlock it?
Voice in the distance: Mr. Fife has the key.
Admin aide: Oh. Okay. Someone stick your head out the window and yell REALLY LOUD for the police.
Pull the damn fire alarm.....The police always come with them.
You need pocket doors that can be closed along a long hallway. Put the PERP in a box...not the kids.