With proper training the use of stun gun could save someones life as an alternative to a firearm. Obviously this is no match for an assault weapon like the one used in Newtown CT but its better than being defenseless. Who knows what could have been had these teachers and staff had access to stop the assailant with a stun gun? It certainly sounds like these teachers did their best to stop the assailant.
Unlike arming teachers or others with firearms in schools it provides a safer means of securing the situation.
While this is not the only answer its worth pursuing even if it only saves one life.
A ban on assault weapons alone will not be enough when the victims are defenseless.