In one scene, Cameron (Summer Glau) is undercover in a ballet class. In reality, Summer Glau is a trained ballerina.
After The Terminator (1984) was released, Harlan Ellison threatened to sue Hemdale, the production company, for plagiarizing two The Outer Limits (1963) episodes he wrote. Soldier (1964) (loosely adapted from his short story "Soldier From Tomorrow") dealt with a human soldier from the future accidentally sent back to our time along with his equally human enemy. Demon with a Glass Hand (1964) has a robot sent back in time to preserve mankind when (in the future) Earth is conquered by aliens. Both of these narratives deal with future soldiers sent back to our times. But the idea of a genocidal war between humans and machines with robotic soldiers made to pass as human can be traced to Philip K. Dick's short story "2nd Variety".
The title of the episode, "The Demon Hand", is an allusion to a short story Harlan Ellison wrote which was, in part, the inspiration for James Cameron in forming the story of the original Terminator movie.
When Summer Glau was dressed up as a traffic cop (in homage to Robert Patrick in Terminator 2: Judgment Day (1991)), she had to have the iconic reflector sunglasses taped onto her head because they were too big.
Lena Headey's meltdown scene in the flashback to her days in the mental hospital was achieved in one take.