Ellison took the Terminator's hand from LAPD evidence and is keeping it in his freezer! Sarah, not realising it might be there, looked around and took one of the video tapes of herself in the mental hospital. John, probably driven by curiosity, took the tape into his room and watched it. The specific tape was of her relinquishing her parental rights over John, probably the reason she took that specific tape but imagine how it looks to a teenage boy, who has one parent in the world.
When he finally comes home, he ends up confiding in his uncle.
Silberman has come to believe Sarah's story and actually tortures Ellison! Ranting about religious signs, he actually talks about the day Sarah broke out of the hospital and talking as if Sarah is some sort of messiah, he is prepared to kill Ellison to protect Sarah. Silberman apologises to Sarah for doubting her and she repays the apology with a well deserved punch. She retrieves the hand and Ellison survives. In a very fitting move, Ellison has Silberman committed, in the same room Sarah was in.
Cameron finds Andy's partner who admits rigging the chess match so the Turk would lose, so that he could sell it. Cameron shows a shocking lack of interest when she walks out on the partner and his sister, not even caring as they are killed while she descends the stairs.
Very sweet scene where Sarah explains her actions on the tape to John. It was the day she escaped.
Gotta say, Derek is incredibly hard to like, he just doesn't have Kyle's sweetness, but his bizarre relationship with Cameron is intriguing. Loved the look on his face as he watches Cameron dancing. Summer, being a dancer in real life, is incredibly graceful.
Very interesting and touching episode.