Cass Fermazzi's gunship

During the Last Great Time War, Cass Fermazzi crewed a gunship for four years, surviving the Nightmare Child, seeing the massacre of Skull Moon, and fighting in the ruins of the Ulterium.

One day, Cass and her crew fought off a Dalek fleet from the feeding hives of the Vantross, but, after departing, they were fired upon by a Time Lord battle cruiser, who were firing on the retreating Daleks, unconcerned by the gunship. (PROSE: The Day of the Doctor) As the only one who wasn't panicking, Cass teleported the rest of the crew off the ship onto the nearest planet before making a call for help, which was picked up by the Eighth Doctor. He materialised his TARDIS on board and tried to rescue her, but, recognising him as a Time Lord, Cass chose death, professing that the Time Lords were no different from the Daleks, deadlocking the Doctor on the other side of the door from her. The Doctor refused to leave her side, even when it meant he would also be killed in the crash. The ship crashed into the surface of Karn in a massive explosion killing both Cass and the Doctor.

Though Cass' body was recovered by the Sisterhood of Karn and they were able to revive the Doctor, her injuries were too severe for even their Elixir of Life to heal. Her death was the catalyst for the Doctor to finally take part in the war. He claimed her bandolier as a reminder of what he would be fighting for and chose to regenerate into a warrior. (TV: The Night of the Doctor)