Hearing Dean's request, Little Mike felt it might alert the enemy, but he still chose to comply. Dean was the only one of his kind in this world whom he acknowledged. His thinking was quite simple: he reasoned that if he himself wouldn't do anything stupid, then Dean wouldn't either.
To reduce the risk of exposing himself later during the operation, Dean had Little Mike wait until the people on the freighter brought up food and water before they made their move. When the time came, Dean would go forward to help with the carrying and then pretend to fall overboard when Little Mike initiated his plan. This way, even if Dean reappeared in public later, his excuse would be solid: an unknown force had attacked the island base's communication network. This caused the experiment to spiral out of control, disabling all the collars. Consequently, Dean had managed to leave the cruise ship without dying instantly. As for how he survived the sea, that would require another suitable excuse.
