[familyop]

"With four deputies on scene, I fail to understand why the officers didn’t enter the school."

If there was only one patrolmen there, he should have immediately gone in and stopped the suspect. We're not discussing a hostage situation.

"Is there a policy regarding possible multiple shooters, that prevents it?"

Not with murders in progress. It's not a hostage situation.

"Seems once you have two or more deputies, you make a move."

One. If there's only one, he must immediately go in and stop the suspect who is trying to murder people. It's not a hostage situation, and there's no time to lose.

Many locales are about to get a long needed housecleaning.

[DoughtyOne]

We’ve been over this, so I’ll leave your comment as is.

Take care.