This is EASY
Someone has a gun. He is either going to rob and/or kill me. He ALREADY threatened to harm me. I know who he is since I used to work with him. He knows I know who he is. I am the perfect witness. I MUST be eliminated from his point of view.
Therefore:
I MUST do whatever I can to avoid being under his control. He may be wearing a bulletproof vest under his clothes. I am good enough with my gun to make a head shot. I wait for him to turn away for a second to pull my gun so he doesn't see me do it. I shoot.
End of story.
Therefore:
I MUST do whatever I can to avoid being under his control. He may be wearing a bulletproof vest under his clothes. I am good enough with my gun to make a head shot. I wait for him to turn away for a second to pull my gun so he doesn't see me do it. I shoot.
End of story.
