Movie Trivia!

[Darth Tepes]

It was done by her....."Sister! She has a twin sister. Your questions have now betrayed her, too."

Her sister's name is Leslie Hamilton (Gearren) and when people talk about identical twins in this case they were TOTALLY indistinguishable from each other.
And sorry for the poor Darth Vader impression.

Correct!  For the scene when they were patching up the t-800 the back of Sarah was her sister while the "reflection" was Linda facing the camera through a mirror frame.  They matched each others movements to make it seem like a reflection.

[Darth Logos]

It was done by her....."Sister! She has a twin sister. Your questions have now betrayed her, too."

Her sister's name is Leslie Hamilton (Gearren) and when people talk about identical twins in this case they were TOTALLY indistinguishable from each other.
And sorry for the poor Darth Vader impression.

There is an alternate scene in the Director's Cut, where the T-800 furthers the explanation of how his CPU works; that there is a switch that is defaulted to follow orders only, and that if it is manually toggled, he will then be able to learn and adapt. So there's this whole thing where they cut open his head to get the CPU, and Sarah tries to smash it with a hammer.