Death Zone Slate Cliff Cavern Entrance

The jagged slate cliff cavern entrance marks the boundary between the Death Zone's treacherous terrain and the relative shelter of the tunnel network. Its dark opening yawns wide enough for a Raston Warrior Robot to step through without apparent effort, yet its slate-gray walls amplify every sound of the charging Cybermen's approach. The entrance's sheer drop creates vertigo for Sarah Jane, while its constricted breadth forces both humans and Cybermen to funnel through in single file—making it perfect defensive chokepoint. When the Doctor retreats to nearby boulders for cover, the entrance becomes a point of inevitability: the Cybermen must breach it to continue hunting, and the Doctor must either hold that line or find another way out entirely.