Gillestes

 was a Yevnon student at the Time Lord Academy. She used Braxiatel's matrix codes to find out the plan of the pumping station. She was found by Andred, whilst he was trying to avail capture, when trying to get a canister into the Capitol water supply. She was a Free Time agent with a Time Lord superior, even she did not know who it was. (AUDIO: Pandora)