Through the controlled Professor Travers, the Great Intelligence explains that it brought the Doctor to London in order to drain his mind of all his knowledge of time and space. Unless he submits to the Intelligence, it will drain the minds of Jamie and Victoria instead. The Intelligence gives the Doctor 20 minutes to submit. Travers is released from the Intelligence's control and is taken as a hostage by the Yeti along with Victoria at Piccadilly Circus tube station. The Doctor and Anne work on the control box further and successfully reprogram a control sphere, which they load into a disabled Yeti to make a covert, voice-controlled ally within the Intelligence's ranks.