The Doctor Falls
Rexhill was a humanoid on the solar farm Floor 0507 of a Mondasian colony ship.
He regularly shot down the invaders from Floor 1056. Shortly before the Cybermen invaded his home, Nardole asked him to fire his rifle at a tree, which he made appear to cause it to explode, surprising Rexhill greatly. He later informed the group that the Cybermen had withdrawn due to the continued explosions. (The Doctor Falls)