I have no law enforcement training or knowledge, but from my armchair, wouldn’t one of the first moves be to put a fiber optic camera up to the window from the exterior of that room to see how things were configured? If they saw the carnage inside, I suspect they would have gone instantly. But perhaps their protocols assume it’s time for hostage negotiations, etc. If that is true, it’s time to change protocols.
This incident should take the wind out of the sails of gun control legislation as a solution. “When seconds count the police are just minutes away” has been validated by this horrible event. And the implication of that is the polar opposite of gun-free school zones.
“...fiber optic camera...”
Might be a bit fancy for small-town Texas.