[M. Bison]

Combat medics are protected under the Geneva convention and considered civilians as long as they don't use weapons. Japan never ratified the Geneva convention. So during Pacific War of WW2, Japanese soldiers were trained and advised to target and kill medics before any other troops. In modern times, combat medics tend to carry weapons and the same uniform as typical troops, and so generally aren't covered under the Geneva convention. If you wanna look up the laws of war then check Wikipedia. Hopefully that answers your question.  :-X