At questions is the officers refusal to obey a lawful order. In the Navy those orders are signed by the CNP not the President. I doubt Army orders are signed by the President. Therefore he is disobeying lawful orders from a senior officer. I was not a JAG, but I have dealt with similar issues.
Army OFFICER oath of Service:
I (insert name), having been appointed a (insert rank) in the U.S. Army under the conditions indicated in this document, do accept such appointment and do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic, that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter, so help me God.
The Difference being in the Word/entity “president”.......
Therefore the orders come directly from his "senior officers" and not directly from the President.
But you forget that the CNP gets HIS orders from the president.