Tracker (2001)

Season 1: Episode 16

Cole gets hold of a tape made at the train station when the passengers from the alien-intercepted train arrives. He identifies one of them as Yahir, an aide of Zin's who may have vital knowledge of Zin's plans and the metal triangle Mel's grandmother has. Yahir's body was that of Rudy, a mental patient who has since been taken back to the asylum. Cole poses as a mental patient to reach Rudy and cuts off his dosage so that he can be interrogated about Zin's master plan. Things go amiss when Rudy/Yahir gains his memories back, drugs Cole, and tries to escape with Mel. Cole manages to escape with the aid of his fellow patients, and stops Yahir just in time, capturing his lifeforce before he can gain any information except that the triangle is a key of some sort, capable of letting the prisoners return home.