Rachel McMahon - the supposed proper spelling according to TimeDude.
Talk about it here.
Rachel McMahon, designated Number 5, was a soldier in the Blue Fire Project. She had "mind wipe" syndrome, as she referred to it herself. She thought, when she first met Dr Magnus Soames, that he was strangely familiar. She couldn't remember her personal life, such as family and friends, but could remember less personal things, such as politics and the news. She was aquaphobic. Water made her anxious, she didn't like still and running water. When she and Toby Dodds got lost in a maze, she heard the sound of water and drowned. The place where she died was devoid of water, and it wasn't raining. Outside the system, she helped the Seventh Doctor to defeat the Mi'en Kalarash. (AUDIO: House of Blue Fire) Template:Namesort