This is unfair to the cops at Columbine. They did not go into the building because they were following doctrine, which assumed the situation would turn into a hostage negotiation, and a gunfight would increase casualties.
As it turned out, the doctrine was totally wrong for a situation where the attackers were just killing people, not taking them hostage. But saying the cops were cowardly is condemning them with the benefit of hindsight.
Apparently rigging a cherrybomb to a door is sufficient to cut the legs out from under a “hot entry” by the Police - as they patiently wait for a bomb squad - while people were being killed.
That is not so much hindsight criticism of the Police as it is ridiculing them being outsmarted emasculated and rendered powerless by two psycho High Schoolers and a small pipe bomb.
Then let us not forget the brave brave officers at Virginia Tech - cowering behind trees as students stood out in the open recording with cell phones. The students with cell phones were displaying more bravery ‘under fire’ than the LEO’s hired to defend them.
One of my favorite lines in Battlestar Galactica is when Apollo advises the President that they have been boarded by Cylons and to ... ‘keep moving, stay away from main corridors, and head away from gunfire.’. The President agreed and was about to turn away when she grew concerned “What about you?” she asked. With a grin he replied “We are headed TOWARDS the gunfire.”.
That is what those charged with protecting the citizenry should do - head towards the gunfire.
My point being that if there was a report of a stabbing - the officers were obliged to go through a bit of danger (a yard with a pit bull) to see if there was in fact a citizen bleeding to death; rather than retreating to wait for animal control - much as the Police at Columbine thought they should wait for the bomb squad.