I can’t think of a single kind of situation requiring a police response where surprise escalation is a key component that will help solve that situation in favor of controlled investigation and a focus on de-escalation.
surprise escalation into an unknown, unverified situation where the only basis for the use of deadly force is whether the police feel there is danger. Of course they are in fear for their lives because they are leaping into the unknown, unprepared.
We hear about the militarization of the police. I hate that term. They are playing soldier, not acting it. Having been in the military, if we had a situation and the time we would monitor a location and find out everything we could. Apparently that wasn't passed along to the police, only the guns were.
Ironically the standard US response for an active shooter in a school appears to be to wait outside for a good while and see if things work out for themselves.