Look, obviously there are some rare situations where de-escalation is not possible, like the North Hollywood Shootout, but it sounds like you're saying that the police should come in guns blazing whenever they think a suspect is threatening lethal force. That's obviously wrong. Police should try, to the greatest extent possible, to avoid shooting anyone. Whenever possible, they should de-escalate the situation, which refers to stuff like this:
> De-escalation more broadly refers to the strategic slowing down of an incident in a manner that allows officers more time, distance, space and tactical flexibility during dynamic situations on the street. Applying these specific skills increases the potential for resolving the situation with minimized force or no force at all, which reduces the likelihood of injury to the public, increases officer safety and mitigates the immediacy of potential or ongoing threats. A reduction in use of force incidents also reduces community complaints, promotes the perception of procedural justice and, most importantly, promotes resolution of events with the public’s compliance. [1]
Here's one case of what not de-escalating looks like, and the kinds of police attitude problems that are at play here:
> “Last week, there was a guy in a car who wouldn’t show me his hands,” the officer said. “I pulled my gun out and stuck it right in his nose, and I go, ‘Show me your hands now!’ That’s de-escalation.” [2]
[1] https://www.justice.gov/opa/pr/justice-department-applauds-a...
[2] https://www.nytimes.com/2015/06/28/us/long-taught-to-use-for...