If they listened to him then they were derelict in their duty. He wasn’t their commanding officer, and his orders should have had no bearing on their actions.
Except that the dispatcher echoed Peterson’s instructions.Best you can say, they didn’t exercise initiative and “ride to the sound of the guns.”
Multiple gunshots inside a school is a desperate situation. Desperate response is indicated.
All of which would have been mooted by preventing Cruz from following through on his threats.