The group are joined by Colonel Lethbridge-Stewart and Private Evans, the sole survivors of an ammunition detail which was attacked by Yeti at Holborn tube station. Lethbridge-Stewart assumes command of HQ from Knight. The web expands enormously, engulfing the whole of the Circle Line. Further attempts to use explosives to halt the web are blocked by Yeti attacks, and the military's explosives store is consumed by the fungus. The Doctor discovers a Yeti-attracting beacon at the scene, convincing him that someone at HQ must be in league with the Intelligence. Meanwhile, Chorley, who intends to desert and flee, is told of the TARDIS by Victoria and he rushes off to Covent Garden to find it; the Doctor, Jamie, Victoria and Evans rush to intercept him. When they reach Covent Garden, the Doctor's party discover it to be barred off by fungus. While they are gone, the base is attacked by Yeti, killing several of the soldiers and knocking out Anne and Professor Travers. The Yeti then leave with Professor Travers' unconscious body.