[Batpuff]

Well to give a little professional insight. and being one that was trained to responded to school shootings. From what I have seen and heard they (police) were doing what they were trained. They are trained to go toward the shots and at a slow but quick pace. And if they encounter wounded or unwounded they are told to head toward the exit were other are waiting to get them to saftey. So it could take a longer if there is a lot of open doors. Ok then you have to taken in the stairways. Theres a certain way that they have to climb the stairs that takes even longer. So its not they just rush in and get the bad guy. And usually its one 6 man team that goes in.