At that moment Robson returns, crying that the rigs mustn't be destroyed. He then runs away again. The Doctor enters and tells Harris that they were unable to find any trace of van Lutyens. He warns Harris that Robson is probably under the control of the creature. 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.