Bro, if you are ever in that same situation, you act. Our job is to save lives (especially kids). Head to the sound of gunfire and neutralize the threat. I think I still have some powerpoints and training materials, IM me if you're interested.
The other messed up part of this is that these idiots have made life so much harder for other first responders all around the country.
Prior to Uvalde, my response would have been to totally trust that the on-scene responders were trained up to do the right thing. I would have been able to fight off my impulse to rush the school myself for fear of making their job harder. Now? I'm rushing my grandsons' school myself if there is even the hint of hesitation by the responders.