A surprising number of Medals of Honor have been awarded for disobeying an order. For example:
The President of the United States of America, in the name of Congress, takes pride in presenting the Medal of Honor (Posthumously) to Technician Fifth Grade Lewis R. Hall, United States Army, for gallantry and intrepidity above and beyond the call of duty on 10 January 1943, while serving with Company M, 35th Infantry Regiment, 25th Infantry Division, in action at Mount Austen, Guadalcanal, Solomon Islands. As leader of a machinegun squad charged with the protection of other battalion units, Technician Fifth Grade Hall’s group was attacked by a superior number of Japanese, his gunner killed, his assistant gunner wounded, and an adjoining guncrew put out of action. Ordered to withdraw from his hazardous position, he refused to retire but rushed forward to the idle gun and with the aid of another soldier who joined him and held up the machinegun by the tripod to increase its field of action he opened fire and inflicted heavy casualties upon the enemy. While so engaged both these gallant soldiers were killed, but their sturdy defense was a decisive factor in the following success of the attacking battalion.War Department, General Orders No. 28 (June 5, 1943).
The contrast, incidentally, between this sort of disobedience, and the disobedience that involves killing a child so that you can brag falsely to your friend back home that you used your knife in action, is rather stark. What matters for the realist project is that we can tell the difference.