Jeez, ya think, Principal Victoria? The worst part of it, really, is that episodes like this just serve to indoctrinate kids even more into this sensationalist cult of fear that's going. They are far more likely to die in a car crash, or at the hands of an abusive relative, than in a random act of senseless violence.
Preparation is important, and violence is real. But these things tend to go wholly unaccompanied by even the pretense of proportion and sensibility. It's just emotional button-pushing, the needless ramping-up of fear.