A teacher concealed carrying a firearm would be a choice, and is in Texas as with School Marshalls. This authorization requires training greater than a concealed carry permit but less than a Texas Peace Officer. Self realization that this responsibility is not suited for you is the first step, but for others it would be suitable, such as a veteran who got into teaching through the Troops to Teachers initiative. This is only a mild deterrence as some with thus goal will sort it out somehow, but an armed intervention will reduce the severity of the situation, as in quantity. My opinions are formed based on being a Texas Peace Officer for 4 years and seeing the most effective handling of any kind of crime was when those on the scene intervened (citizens arrest, detaining, armed intervention, etc..) law enforcement can get there from however far they were when they were sent there. And from my experience, When things go bad, even with light, sirens, and the car going as fast as it would, I could not get there quick enough.