"... perhaps even his own, because rather than simply shielding students from gunfire, he could have drawn his weapon, fired and killed the assailant — putting a tidy end to the rampage. This is absurd. More likely, had Mr. Feis been armed, he would not have been able to draw his weapon (a side arm, presumably) quickly enough to stop the shooter, who with an AR-15 would have had the coach outgunned. Even if the coach had been able to draw his weapon — from where? his athletic shorts? — any shots he managed to fire would have risked being errant, possibly injuring or killing additional students. As some studies have shown, even police officers have missed their targets more than 50 percent of the time. In firing a weapon, Mr. Feis would have only added to the carnage and confusion...."

From "I Was a Marine. I Don’t Want a Gun in My Classroom" by Anthony Swofford (NYT).