That may be your opinion. I doubt the police officers who respond to active shooters would share your disregard for their lives though. Even if you think their deaths are acceptable, they likely won't, and will still go in ready to kill - or won't go in at all if they aren't permitted to defend themselves.

Again, the question is really which option is worse. On the one hand we have a zealous police response that will sometimes kill innocent people as a result of things like swatting, being unintentionally misinformed, or even just tragic accidents. On the other hand we have a cautious police response which might minimize the people injured or killed by the causes just discussed but increase the injuries or deaths that result from delays in police response. Which of the two causes the most harm?

As I've said before, my intuition is that a rapid response is the least harmful. I think the policing experts in charge of current policing strategy share that opinion based on current protocols. I understand that you prefer the cautious strategy, but I haven't seen you explain why you think there will be less harm from that strategy.