Wow. Hadn't considered the JW angle. Ok, boyfriend it is then. That's a tough row to hoe, and I salute you for it. As for everybody else, opinions are like hinders. Everyone has one, but only a few are worth giving a second look.
As for your future command, I will try to explain to the best of my knowledge. As an O3, you will probably outrank your surg techs, nurses, lab techs and other support staff. You may be working with other O3 doctors, or they may outrank you. You will also have a chain of command overseeing you, which may consist of people in the Medical Corps (doctors), Nursing Corps or Medical Services Corps (lab tech, etc). Mostly, this will just facilitate the day to day doctor stuff, and I don't see how the nuts and bolts would be any different than a normal hospital. Support staff will still defer to you as the doctor for medical judgement, etc.
Now, as far as downrange, lets say you are a Battalion surgeon attached to an infantry unit. As you're not a combat arms officer, no-one will expect you to take charge of a platoon and start kicking down doors. Under those circumstances, it would seem to me that you would maintain command of the medical services, or default to 11B (infantryman, if your position is overrun, all bets are off and you pick of a rifle), while the senior officer/enlisted present with the appropriate MOS will be in charge based on their MOS circumventing your rank. Make any sense?
The 11B Staff Sgt or 1st Lt would be in charge over you, combat wise, because they would have operational control. Just like if you were performing an operation as a surgeon, a higher ranking nurse couldn't come in and order you to alter your surgical procedure, because you have operational control based on your MOS.
So, until you are an O4, I don't really think that you "command" anyone, functionally. Once you're a Major, then you'd be in command of your medical group.
I may be wrong on this, so if anyone is more enlightened than I, please share.