Not really. There have been phone calls to 911 during school shootings but reading a few reports, it's never made a difference since schools tend to be hardwired straight to dispatch which is most important. Big failings like Uvalde has been terrible response by first responders which is "Push forward till threat has ended."

Yes, parents have been called by students during incident but that generally makes situation worse as parents run to the school causing delays for first responders.