We had some crazy topics in our assemblies at school, but nothing quite so spectacularly irresponsible as this - even that intensely irritating and unfunny little beardy twat, Jeremy Beadle, never stooped quite this low. He'd probably just smash a crane into your car, knocking it into a canal.
Apparently the theme of his assembly was "Live for the moment". Now I fail to see just how abusing your position as headmaster of a school to tell your pupils they're all about to die is in any way going to teach them anything useful. Perhaps the theme of the assembly should have been "Our headmaster is a f***ing c**t".
A similar thing once happenned to a friend of mine, when she needed to ask her boss a question for an important customer who was on the phone. She had to get her boss out of a weekly meeting with Senior Management to consult with him, but needed an excuse to interrupt the high level meeting. In the end, the best she could come up with was to run in and say "Steve, Steve, come quickly, your wife's dead". Well, she lost her job over this and this was just one man, not 230 pupils.