Actually, the more facts that come out about Columbine the more you realize the cops did the same thing there. One of the teachers died bleeding out because despite the kids holding signs and other teachers telling cops he was in trouble the cops chose to search another side of the building and not send EMTs. It took like 45 minutes after they entered the school to get to the room (the shooters were dead by then) and the kids couldnt hold off the bleeding long enough.
The cops flubbed Columbine and then covered it up in such a haphazard manner that their lawyers should work for Trump. At one point while being sued they sent out all the police reports and were so lazy that when they "forgot" to send some pages didnt realize all the pages were numbered. So the defense saw "Page 45, 46, 47, 55, 56...etc." and realized they had been lied too. They are still suing for all the info to this day. (there was a book just written about it which was discussed after Uvalde)
At least in Columbine's case it was new...Uvalde was trained for this.