When the base was taken over by Ice Warriors, they ordered Phipps to assist Fewsham in repairing the damage Osgood had done to T-Mat. Instead he and Locke repaired the video link to Earth to warn them of the invasion. Locke was killed, but Phipps escaped and hid within the base.
In the solar energy room, Phipps developed a trap that used solar power. With this, he killed an Ice Warrior by exposing it to extreme heat which disintegrated the Warrior. The solar power also allowed him to radio the Second Doctor, Zoe Heriot and Jamie McCrimmon as they landed on the Moon.
He rendezvoused with them and once again evaded capture by the Ice Warriors. Phipps decided to assist Zoe in turning up the base's heat. They traversed the base using the ventilation shafts. Within them Phipps began to display signs of claustrophobia, so Zoe allowed him to rest.
They made it to the control room and Zoe turned the heat up. As she did so, an Ice Warrior caught sight of her. Phipps shouted a warning — alerting the Ice Warrior, who killed him on sight. (TV: The Seeds of Death)