To get the mission briefing, Jim asks the store clerk for "Pavane in G", the same piece of music Dan Briggs asked for in Pilot (1966) .
Jim Phelps ( Peter Graves ) describes Cinnamon Carter ( Barbara Bain ) to Captain Olni ( Noah Keen ) as "in her late 20's". Bain was in fact 37 at the time.
The testing room is reused, slightly redressed, as the master control room in The Glass Cage (1969).