Well, to put into context: the police at Columbine ALSO waited to enter the building until Swat arrived (I forget how long, but it was a fairly significant amount of time). They exchanged gun fire with the boys from various windows at several points during the event. After the two had killed themselves, the officials also took hours before they evacuated people. This resulted in the death of a teacher who bled out waiting for help in a classroom. Now, having said all this: This is PRIOR to "engage and rush to target" training that became common place after this event. Responding officers are trained and instructed that in an active shooter situation to run to the gun shots and stop the threat at any cost, leaving all casualties and civilians to fend for themselves until the threat is neutralized. This recent shooting (assuming it wasn't a glowie psy op, which I'm of the opinion it was) had zero excuse for what happened.