Jevvan

 was a member of the cable maintenance crew. She moaned about the state of the cables to Gerium and Tin-Marie. She ran a diagnostic when the power failed. She met the Seventh Doctor in the tunnels, when she was looking for Tin-Marie. She like cheep and tacky. She disliked the termites. She saw that the termites were moving the city. She used the technology in the TARDIS to help the Seventh Doctor to defeat Our Mother. (AUDIO: Valhalla)