This ship has never encountered mechanical failures; its navigation system is something he's never seen before, usable only by specially trained technicians.
These technicians include the ship's doctors, nurses, experimenters, and inspectors, all assigned by the Shield headquarters.
The captain has no authority to hire or fire them, and their work independence and confidentiality are very high; they can directly contact headquarters to report work, the captain has no right to intervene.
Thus, on the ship, only the regular crew members are managed by the captain, responsible for lookout, cleaning, and security work, much like gatekeepers, cleaners, and guards.
Additionally, he received a peculiar order requiring him to periodically send people to the hold, tossing them in the night before and releasing them the next morning.
The crew are his old subordinates; he can't toss his own people, so he kidnaps fishermen on the high seas or tourists with few numbers, easy to handle.
