The answer to this is simple. Once they cornered the guy in a single classroom they paused to get organized. It didn't matter than a dozen or more injured students were in the room with the gunmen bleeding out while they took a doughnut break. I bet when everything is said and done half or more of the dead were in that one room and most died because they didn't get medical help for 30+ minutes while the police figured out what to do next.
The answer to this is simple. Once they cornered the guy in a single classroom they paused to get organized. It didn't matter than a dozen or more injured students were in the room with the gunmen bleeding out while they took a doughnut break. I bet when everything is said and done half or more of the dead were in that one room and most died because they didn't get medical help for 30+ minutes while the police figured out what to do next.