Brownie, I'm not sure about #2 as you've stated it above. I don't think if I was approached by someone I knew was armed, such as a person walking up to me at the gas pumps with a knife in their hand, that I'm going to spend a single second trying to figure out what their motive is. It seems to me that I'd put your last quoted sentence into the #2 spot and leave figuring out the motive to police and prosecutors. Means, opportunity, and reasonable fear of death/GBH would be all I'm looking at to complete the firing circuit. Motive, not so much. How would I know the motive until they've acted?No matter what scenario one examples from the real world in a link here, or reads a scenario made for members to discuss options, there's some hard and fast rules for deadly force use.
1. They have to exhibit a means to cause death
2. They have to clearly have a motive to do great bodily harm or death upon your person
3. They have to have the opportunity to cause grave harm of death to you.
All the above with the lawful caveat the threat of grave bodily harm or death is IMMINENT.