The previous school my wife taught at was a tiny K-thru-8 Catholic school with an inexperienced principal with no leadership skills. Same drills every semester - lock the doors, close curtains, lights off, cower silently. A couple weeks after the drill while it was still fresh in everyone's mind a 5th grade boy acted out all day then snuck into the kindergarten bathroom to hide before the last period. Principal put the school on lockdown while they went through the school looking for him. Most everyone knew what was going on since gossip spreads faster when the student has already pissed off half the teachers that day, and someone had gone to most of the classrooms asking "is X in here" before the lockdown started. But at dismissal all of 6th grade and the art teacher were missing missing because nobody had called off lockdown, so they had been in their somewhat isolated classroom in the dark for 45 minutes, waiting their turn.