Especially if the armed folks in the schools are not uniformed and obvious. The killer kills the guard first or when the guard is at the south door, the killer goes through the north door. Let it be known that some of the teachers and staff may well be armed. Who and where that teacher (or janitor) with a gun is must remain a surprise.
Really? As I recall, two school resource officers prevented school shootings within the past two months, one in Great Mills, MD and one in Dixon, IL. Besides, I’d rather have them shooting at an officer than at other kids.