Vallance's transformation from a member of the Wheel's crew to a hypnotized agent of the Cybermen, embodying the Cybermen's infiltration tactics and raising questions of trust and control.

Flannigan enters the Power Room and immediately senses something amiss with Vallance and Laleham, who evade his questions about the laser’s status and react aggressively when he presses them. Vallance …

In the oxygen supply room, Corwyn—now the acting leader of the station—witnesses Vallance, under Cyberman control, entering with a small box of silver capsules. A Cyberman directs Vallance to insert …