Last time I was seriously worried I had 7 thugs with baseball bats and knives at the back of the school - drug dealers upset that I was in their way in the car park. The police arrived 45 minutes later, at the wrong place - of course with stab vests and batons and sprays etc. I couldn't ask other staff for help as they would have been too endangered. Just me (aikido) and the caretaker (jeet kun do) to do the necessary. We did, they left - fast, hurling abuse. All the bravery of bullies - two down and the rest left rapido in their cars. That was frightening for me after x decades of training. How the hell could I expect some poor teacher 'on duty' to cope? We need full time security as well - sad ain't it!