Ruth Matheson

Ruth Matheson was a captain who was in charge of the Vault.

Biography
Matheson gave Charlie Sato a tour of the Vault when first became its warrant officer. In the Vault they came across four objects: An army jacket, a painting, crystal and a wax cylinder, which bore a significance. Each was used in one of the Doctor's many adventures. (AUDIO: Tales from the Vault)

Matheson and Sato were tasked with guarding the Master. This task was unsuccessful, as the Master managed to trick the duo and escaped in his TARDIS. (AUDIO: Mastermind)

After the escape of the Master, Matheson, along with Sato, was relieved of her duties at the Vault and 'reassigned', having been deemed a Category-One Security Risk due to the risk of the Master placing any post-hypnotic suggestions inside her mind. Relocated to a private residence for compromised UNIT personnel, Ruth believed that any tampering made by the Master would wear off in time, and so kept herself busy by completing several degrees, unlike Sato who felt that his career, and life, were now over. However, they earned a brief reprieve when they were recruited back into active service by Mike Yates, who needed their help to investigate what had happened to the Vault during a communications blackout and subsequent loss of contact with several investigative teams. (AUDIO: The Screaming Skull)