What they needed were cops with actual backbones instead of ones standing outside for an hour. I have a hard time believing that if a mom could run in there and get her own kids that the police couldn't have done the same.
Hell, they were already in there rescuing their own kids:
https://www.yourtango.com/news/uvalde-police-officer-admits-cops-saved-their-kids-robb-elementary-before-stopping-shooter