After seeing the NM cop get attacked with that knife in that horrific video, I’d be shooting as soon as I saw a glimmer of steel. Tueller drill, yo.
All of these “fear of life” certitude arguments fly in the face of reality. The Mythbusters tested the “Bring a knife to a gun fight myth” and found that 90% (If I recall correctly) of the time, a trained guy with the knife WON the gun against knife fight when it started 21 feet or less away. So the distances of most in-house, or person-to-person encounters, the guy with a knife has a nine to one edge if they are at all aggressive.