I’m assuming you’ve never been either Enlisted or an Officer in the military then; as the military makes such a big deal about the qualifier “LAWFUL” in its briefings to the enlisted.
You assume wrong. I spent most of my adult life as a commissioned Naval officer, active duty and reserve.
...; as the military makes such a big deal about the qualifier “LAWFUL” in its briefings to the enlisted.
Indeed it does. In fact, it goes farther than making a big deal but actually defines it. According to the Manual of Courts Martial, "An order requiring the performance of a military duty or act..." - like reporting to the office of your brigade commander or reporting for duty with another unit - "...may be inferred to be lawful and it is disobeyed at the peril of the subordinate." The MCM provides a single qualifier: "This inference does not apply to a patently illegal order such as one that directs the commission of a crime." The MCM also states who will decide if an order is lawful or not: "[t]he lawfulness of an order is a question of law to be determined by a military judge." Nothing gives Lakin the power to decide on his own if an order is lawful or not, absent any obvious criminal aspect to it. It does provide that the order "must not conflict with the statutory or constitutional rights of the person receiving the order." And that is the only constitutional clause mentioned, and nothing in the orders that Lakin disobeyed interfered with his constitutional rights. So by any rule or regulation you would care to name, Lakin disobeyed the lawful order of his commanding officer. And he will suffer the consequences.