Infuriated by Liz's rejection, Nancy attempts to bring her under mental control, but fails when Liz begins to fade from existence. Fortunately, the Doctor arrives just in time, and once back in the time bubble surrounding Bessie, Liz returns to normal. The Doctor drives back to UNIT HQ, and as Nancy's soldiers redouble their efforts to destroy the time bridge, he leads the Brigadier, Benton and Yates through the time bridge to the Constitution to face Nancy in the past. Nancy and her slaves are in the process of taking over the ship, and when they attempt to kill the intruders, the Doctor—realising that Nancy is beyond reason—uses his sonic screwdriver to find the resonance point of the ruby crystals. The crystals shatter, killing Tilly and Ferraro, but as Nancy dies she falls atop the ampoule—and the contents spill over her body, the remaining ruby fragments, and the structure of the Constitution itself. Back at UNIT HQ, Liz and Osgood find themselves looking out over a devastated wasteland as the Constitution begins to warp into a monstrous living being. The contents of the ampoule have merged Nancy, Brokk's eye, and the organic components of the ship itself into a voracious living entity, part animal, part vegetable, and part mineral; the transition has driven the new entity insane, and it will consume all life on Earth.