" The defense of necessity is considered a justification defense, as compared with an excuse defense such as duress. An action that is harmful but praiseworthy is justified, whereas an action that is harmful but ought to be forgiven may be excused. Rather than focusing on the actor’s state of mind, as would be done with an excuse defense, the court with a necessity defense focuses on the value of the act. "

― Massad Ayoob , Deadly Force - Understanding Your Right to Self Defense