Assuming the Geneva convention applies. I'm not talking about an unethical order here. If your doctor endangers their own people by going out into the field and lending aid to an enemy, and in doing so is jeopardizing countless more lives, then telling them to NOT do so & expecting them to follow that order IS ethical. Life is not black & white, good vs bad. Ordering an ugly thing to prevent worse things from happening is always a possibility
I was in the medical field in the US Army.
I don't know. I think a CO could order a doctor of lesser rank to not go and aid injured enemy soldier if it was going to jeopardize their own troops.
However military doctors is almost an oxymoron. A doctor might just tell the CO to "go to hell" and do what they want anyway.
In fact thinking of the doctors I knew, pretty well as a matter of fact, I think they did whatever they wanted to do.
They were cognizant of the hierarchy of command and followed the rules in that regard even though there were times they didn't agree.
There would be very little recourse against them at any rate. They could resign their commission and go out and make more money in the civilian sector in about the two hours it might take them to go home change clothes and get a new job. (They tried to court martial an 0-6 where I was stationed. He was head of the ER like a mile from his house about a week later.)
I only knew one that would have taken command of a unit or company though.
He had been in Viet Nam as a new lieutenant there. Then went to medical school. He was about 6 ft 4 inches tall and looked like John Wayne (when John Wayne was like in his 40's) he was the only bad assed doctor I ever met.
Don't get me wrong, most of the doctors were good doctors and behaved in a professional fashion but medicine ruled their lives not some dickweed trying to score brownie points or whatever.
I can see sme doctors being in command and others not at all. Pretty much like any occupation. Plus people can change too.
A bigger question would be is there s fan fiction out there with Captain Reg Barclay?
Or Commader The Womanizer Barclay?
Can someone change that much?