What was the significance of the voice [name withheld] had in his head that kept calling him “Commander?”

This was used by his mind control programming to unlock some things in his deep memory storage. This is a code word they use with him to connect his current experience to prior service and the reawakening within of some inner gateway to allow them greater access to manipulate him in the moment. It is sort of like saying a secret word that opens the safe and allows the stored secret instructions to be reactivated. In his case, he is resisting their efforts at manipulation due to his inner desire to escape from their influence, and this was the reason why he became emotional and began to challenge them, and to challenge the apparent meaning of what was taking place, which to a significant extent was a mystery to his conscious awareness. But the emotional consternation was more than just the surprise and alarming experience of having a foreign voice begin to speak within his mind. It was the very use of that word and its inner familiarity within his mind that was triggering inner fear because, first of all, it represents what he has gone through because of his association with the extraterrestrials. So this is also evidence of the trauma he carries for which healing work will be of great benefit.