welp. I studied in a military school, in Brazil, virtually everybody in the school has a gun on their waistbands, and there is no register of people shooting in there since the school was founded: 1919.

Actually, there is no register of people shooting in any military school in Brazil since the first one was founded: 1889. :v

So, you're right. Giving guns to the teachers isn't the solution, you should give guns to the maximum number of people who are able to properly use a gun in the school. :v

PS.: Teaching to kids how to handle a gun could be a good idea if you make sure to test their psycho-social when they enter the school.