"What do the Cybermen want?" Rosita asks, and even though Freud hasn't even been invented yet the answer's the same: the Cybermen want to take your brain out and put it in a metal shell and for everything to be just like them. For example, cut to Mercy Hartigan, who is now strapped into the chair and arguing semantics -- You can't do this to me! and the guy's like, "Incorrect! For we did it already!" and this kind of thing -- and panicking, because she wants to be the boss of robots and not a robot. Or I mean, at least a friend of robots. She complains that she would have served them anyway, and not only is that clearly untrue because she's awesome, but also because she's not: "Your mind is riddled with anger and abuse and revenge. These have no place in a Cybermind. Activate!" The crown comes down, and the many hurts and lost memories of Mercy Hartigan, the anger and abuse and the revenge, are taken care of. "Emotions have tormented you all of your life. Now you will be set free. This is your liberation." All hail the CyberKing, awakening to a new dawn, her eyes open and black as night.
Looking down into the factory. The kids working, cyubermen patrolling. JL: Upon my soul... R: What is it? It's an engine. It's huge, gears and steam everywhere They're generating electricity. But what for? JL: We can set them free! Calming him: No, no, no, no, no, no, no...
While the Doctor and Companions stare down at the factory and get all heroic and excited, Mercy realizes that being the CyberKing is not all bad. The black eyes are on like every show, eventually. Sometimes they mean demon possession, sometimes they mean you are about to go turboslut at the behest of Dionysus, occasionally they mean you tried to film a threesome and ended up watching some guy accidentally OD on coke which so traumatized you that you had to run through the city with no pants on and have sex with a heavily waxed human Ken doll and then fuck off to boarding school for a year, causing everybody you left behind to break down and become suicidal and bulimic and queer. But here, I guess they mean your brain is becoming tapioca, like evil pudding, because for such an awesome character, Mercy Hartigan just turned into a real shitty character, with a retardedness quotient equaling or exceeding that of the cat-penis octopus-headed Dalek Guido Thing.