Smith pointed his gun at the cop in close quarters. The cop has to fire or die.
You have a limited scenario generator. I can see #3 and #4.
Personally, I was taught to run from a knife and close on a firearm.
Either way it takes quick and accurate thought processes.
Considering how many of the local constabulary I back off from, wave a flash light at, and use a drill pad voice to address while they are lost in the laptop in the police car... their situational awareness is not up to field standards.
/johnny