It seems to me that school district police, aside from the chain-of-command problem, also simply don’t have the experience of dealing with dangerous situations on an almost daily basis like regular police do.
You can see in the video that the officers who responded to the Nashville school were not only well-trained, they were experienced and used to working as a team in a high-threat situation. School district officers simply can’t have that kind of experience and teamwork. It’s like the difference between green soldiers and hardened battle-tested troops in war. Which do you want when there are bullets flying?
The school was also prepared: the woman standing outside to hand keys to the cops, for example. That looked planned in advance, and perhaps even practiced in advance. Sure beats the Uvalde cops dithering over keys while children were murdered.
Nashville seems to have a sort of hybrid plan:
They have unarmed school “safety ambassadors” employed by the school district, plus police resource officers who are employed by the police department and answer to the police chief inside some schools, and also regular police patrolling around school areas to respond quickly in case of an active shooter or similar threat to kids’ safety.
The hybrid model Nashville uses might be the best way, at least it looks that way to me. Of course the small private Christian school did not have a “safety ambassador” or school resource officer, but as best I understand, had worked with police to form their active shooter plan.
The hybrid model looks like a good place to start. The advantage of district police is they know the buildings, and if a dispatcher have access to CCTV they might be able to give a exact or much closer location and they would know say third door on the right, 2nd floor off the main stairs, etc. However, that only helps if they have keys and proper training as you said.
If that is not possible, a staff member, as we saw here, who could advise police upon arrival, but still requires a bit of searching in a unfamiliar building. Always room for discussion and and improvement.
What confuses me the most in Uvalde is how the school police, who are district employees didn’t have keys/key cards or what ever was used. Did every officer need full sets, maybe not. However access to some secure lock box(s) outside the school or the dispatcher being able to remotely unlock exterior doors on their arrival would speed up the entry process.