Jamie searches the refinery complex for Victoria whilst the Doctor explains that the creature's intelligence is the sum of the stolen knowledge from the people it has absorbed. Contact is broken with the rig. Jamie finally finds Victoria in the pipe room and she warns him about Oak and Quill. The Doctor tells the group in the control room that he believes the weed intends to use the rigs as a bridgehead to spread onto the mainland and eventually all over the world. They must find a way of destroying the creature's nerve centre.
Price is now unable to raise any of the remaining rigs.
The Doctor realises that the weed may find pure oxygen toxic but he is overheard by Oak and Quill who immediately go to the oxygen store and empty all the cylinders. Harris discovers that the oxygen supply has been sabotaged and realises they have a spy in their midst. When he begins to check the fingerprints of the personnel, Oak and Quill try and escape, chased by Jamie. Jamie catches Quill, who spits toxic gas at his face. Victoria screams and Jamie manages to land a punch.