to pilot the ship to another country where his skill will be appreciated. Once his work is complete, the Doctor shuts off the ship's lights, hoping to use the element of surprise to retake the bridge—but some of the alien blood splattered about the ship during the earlier battles turns out to be bioluminescent, and the mutineers recover from the shock more quickly than the Doctor had hoped. Only Turlough manages to escape, and remains helpless to intervene as the mutineers throw the Doctor and the engineers out of the airlock. Before the mutineers can dispose of Turlough, the ship unexpectedly takes off, and they reach the bridge to find that the navigator's brains have been sucked out through a hole in his skull. Lytalia, cowering in the corner, tells them that there is a Vrall hidden aboard the ship; a ruthless and cunning killer which must have slipped aboard during the earlier battles. Turlough and the mutineers make an uneasy truce and set off after the Vrall, while Lytalia, exhausted by her recent exertions, remains on the bridge. The Vrall, however, is more dangerous than they had anticipated, and another mutineer is killed before the others can barricade themselves in the engine room. Turlough suggests hunting the Vrall with the acid jars from the impeller drive's batteries, but when he and Stanton emerge from the engine room, the Vrall overpowers them and kills the others—and then squeezes back into the hollow husk of Lytalia's body, where it had been hiding all along. Having disposed of its enemies, it orders Stanton to pilot it back to the Moon, where Turlough will use the TARDIS he described to pilot it anywhere it wishes to go in time and space. Stanton, however, escapes and flees to the cargo hold—and when the Vrall pursues him, he deliberately opens the hatch. He and the Vrall are expelled into space, along with all of the air in the ship... The Doctor's Gallifreyan metabolism enables him to survive the cold and airlessness of the lunar crater long enough for him to find a spacesuit which the mutineers had abandoned to lighten their ship's load. Even so, he nearly dies before reaching the TARDIS, but fortunately the shutdown of the force fields has put an end to the interference which kept Kamelion from emerging. Kamelion carries the delirious Doctor back to the TARDIS, where the Doctor's wandering