Henderson is visible on the bridge when O'Neill tells Bridger about the message from Noyce. But when the shot changes to the break room, Henderson is behind Tony. She is in two places at once.
TRIVIA: In this episode, Piccolo's dyslexia is revealed. This would be a recurring character element throughout the remainder of the series.
This episode marks the final appearance of W. Morgan Sheppard as the hologram of Prof. Martinsen, and the final episode of Richard Herd as Noyce.