So I've raised this twice and both times severe motormouths just suddenly are struck dumb.
HOW DO YOU STOP THE SECURITY OFFICERS FROM BEING KILLED FIRST.
First let me note that most school shootings involve an individual attacker who is a disgruntled student with mental illness issues. The "beef" of these attackers is with other students or teachers -- not with the school resource (security) officers. The attackers generally go for the "soft" target which they have the beef with first, not the "hard" target which is the trained & armed cop at the school.
Has there ever been a single instance of a school resource officer being attacked first or being killed first in a school shooting incident? No.
Armed school resource officers are probably the best deterrent against school shooters -- because the school resource officer does a lot more than provide an immediate armed response at the school. Their actual job is to get to know the students, know who the trouble makers are, know which students are demonstrating risky behaviors that they may become a shooter, talk with the students (and get information on possible threats/problems), and engage at-risk students to be sure they are not bringing a weapon into the building. The role of a school resource officer is must larger than just being a guy standing around who has a gun.

