I now offer for your consideration a “final” installment on my paradigm for the use of deadly force. The posts directly-related, in chronological order, are HERE, HERE, HERE, HERE, HERE, and HERE .
As previously defined, the MUST: If deadly force is not employed, you or someone you cannot live without will likely die. Add, if you wish — the MAY permits, and the SHOULD will normally compel — or suffer great/serious bodily injury/harm. Sprinkle with the required dose of reasonable certainty that deadly force is necessary (something way north of even odds, as the use of deadly force invokes the decision process reserved to life’s most important questions) and imminence (usually meaning within a few seconds, but I often note how the certainty of suffering deadly force, might make much longer intervals considered imminent), and slip on the halo of the non-culpable, reasonable man acting in good faith. (LEOs: I may write a post on your MUST at a later date).