Marjorie Stonegood

 was the daughter of an engineer who went missing. She asked George Augustus to investigate this but he wouldn't. She helped Adric and Nyssa out of the Contigency Club through the tube tunnels. She went with them back into club and found her father there. She untied Nyssa and Tegan Jovanka when they were tied to a set of explosives. (AUDIO: The Contingency Club)