Talpa

 arrested Ace on the orders of Caliban. He had lost his medicine in a skirmish which meant that he could turn massively violent and kill everyone in sight. He told Ace that he believed the humans made the Mogera mutate. He hoped to be promoted. He found it strange that Ace didn't run away overnight. Ace worked out he wasn't mutated because of the Doctor but because of the drugs he took. (AUDIO: Maker of Demons)