Ummm the way i was taught... Deadly force, that force which a person know or whish he should know has a risk of causing death or serious bodily harm.  It use is justified on in the following manner: self defence defence of others. property involving national security  property not involving national security but inherently dangerous to others. Upon lawful order dang i cant remember the other 2 Serious bodily harm is breaking of bone mainming or disfiguring   So even your non lethal strikes are using deadly force.