LOAC and the American serviceperson
Law Of Armed Conflict, our folks get that training before they are allowed to fire for combat qualification. medical personnel also receive their own version of Geneva Convention which is that medical persons fight only to save their lives, their patients lives, and to safeguard their facility and materials. (If you happen to be around the rest of your unit, who are all potentially your patients...just don't take the chain gun and go postal).
(And yes, I know, that red cross makes a dandy sniper target).
Neither LOAC nor Geneva allow for summary execution, nor to allow a prisoner to be summarily executed by others (i.e., put them down handcuffed outside the gates and wait), and that goes double for medical personnel. It's the law, our law.