Martin Flanagan was a resident of Poseidon 8.
Martin was working out on the underwater prairie with the base leader, Pat, when they were attacked by the alien shark. Only Martin survived, but could neither communicate with the base nor go down to it due to Jones's strict implementation of the quarantine imposed by Oswald. The Eleventh Doctor and Amy arrived soon after, and managed to convince Jones to let them through to the base. Martin's reunion with Oswald and Dana was short-lived, as there was a failure in the base's lights and he was devoured by the Vashta Nerada. (GAME: Shadows of the Vashta Nerada)