"And there are no doubt a million other variables that make committing to any predetermined response a naive unhelpful approach. Every situation is different and must be treated accordingly."

Right - but the trouble is that every school is obligated to have "a plan" - no matter how useless or counter-productive; so when the excitement is over and the blame is being apportioned, the school authorities will be able to say, "It's not our fault - we had a plan!"

Incidentally, I'm a teacher too, and be-damned if I'd follow the mandatory sit-and-wait plan with some loonie shooting up the place. By the way, in response to some comments, there are many kids who are much cooler-headed in a pinch than a lot of adults ...