Originally Posted by Superbelt

Actually, the body count may have been only this asshole himself if the cops had taken longer to get there.

This guy didn't start shooting until police started moving in. He was planning on some protracted standoff. Even brought his own change of clothes and 'facilities' with him. He was still working on barring the door when the police were moving in. He gave them a ten count to back off, and didn't feel they were taking him seriously so started shooting before he even finished his count.

If they had gotten there later after he had already barricaded himself, a perimeter could have been formed and sharp shooters may have been able to take him out through a window (not many places to hide for long in a one room, natural lighted schoolhouse).