B is for... Bennett (4)

Mason Bennett was a geologist who was part of the crew of the Drum, an underwater base situated on the floor of a flooded valley in Caithness, in the north of Scotland, in the year 2119.
This was a mining operation, run by Vector Petroleum. Investigating a village that had been submerged when the valley flooded over a century before, the crew had discovered an alien spacecraft and brought it aboard the Drum. The commander, Moran, was killed when its engines fired. He appeared soon after in ghostly form, and began to kill off other members of the crew.
When the TARDIS arrived, the Doctor decided to investigate the spacecraft's initial landing. He travelled back to 1980, taking Bennett and colleague Alice O'Donnell with him. She was killed by the occupant of the craft - which was really an alien hearse. This was the Fisher King, who was creating the ghosts in order to transmit a psychic signal to his kind to come and rescue him - and to take over the planet.
The Doctor sent Bennett back to 2119 in the TARDIS using an emergency protocol, whilst he remained in 1980.
Bennett later admitted that he had loved O'Donnell, but had never told her - so he made sure that colleague Lunn didn't make the same mistake as he, and would tell fellow survivor Cass that he loved her.

Played by: Arsher Ali. Appearances: Under The Lake / Before The Flood (2015).