If someone levels what looks like a gun at you, you be brave and take the first bullet. I’m not asking any public servant to do the same.
You imply that the officers should allow the person to fire off a round(s), by your mention of return fire.
NO!
If I walk into an ambiguous situation and shoot someone who turns out to not really be a threat, I’m in major trouble.
Why should a less stringent standard be applied to cops?