School teaching kids to fight back gunmen

I had always wondered why no one fights back, but then again, unless the swarm is totally effective, spontaneous, and swift (quite a few criterion there already), then I can see people dying anyways. Aiming at the eyes would do the trick, but you'll need something that can cause serious damage, and even then, the gunman might just hope to randomly pull the trigger and spin around with blind fire. Plus, the smart gunmen would probably not let them self get unnerved by sudden noise/change of power :S
It might work with gunmen that have a slight amount of hesitation beforehand, but for those with the intention to kill, then people are definitely going to die regardless of counter tactics. As well, there's also the possibility that potential gunners would read this article and prepare themselves accordingly by setting up countermeasures to these countermeasures, thereby nullifying them.

Jam it back in, in the dark.