[Glenn E. Meyer]

That is the point. These are over quickly in most US situations. You do have some where the killer is stalking the locale and info could be useful. However, even with the most reasonable fastest response - 10s of people are shot.

Note also the response time is based on when the call gets through and interpreted. There is not an instant call. A few minutes have passed and then you get the staging and entry times.

The only reasonable fight response that isn't based on sheer luck in a suicide charge is to use a firearm. Yep, if Mister Stupid Killer walks blindly into a crowd, you have a chance and you can rush him or her. That's happened. If they have a malfunction or fumble the reload you can rush him. But that happens after a wave of fire first.