DELACROIX
In the Spirit of Honore' Daumier
The timelines were very confusing. It sounds like they thought the shooter was barricaded and not a hostage situation at first. Hindsight makes them look like cowards for waiting (possibly true but debatable). The shooter was hiding in a closet and popped out to shoot at the cops when they went in so looks like caution was advised. The big question seems to be how many were killed during the delay and that isn't clear.
We are forgetting that the first responders had to evacuate the rest of the children first and get them out of harms way. Unfortunately all of the killing probably occurred in less than a few minutes, I find fault that the maniac was shooting at the school for 12 minutes before he entered the classrooms.