Charles Whitman?
Whitman wasn’t inside a building with a bunch of “hostages.”
Per Columbine, as I understand it, shots were fired by two cops at the perps as they approached the school.
I want you to just think about what would have happened to the cops had they stood their ground and killed those “children.”
Such action would have been considered appropriate by many only to prevent what happened, which of course we wouldn’t know about because they prevented it.