First episode where characters use the Seaview's ventilation system to hide or move about the ship.
This episode takes place in the 1970s.
Guest stars Jan Merlin and Than Wyenn would less than a month later also appear as guest stars in the episode of The Man from U.N.C.L.E. (1964) titled The King of Knaves Affair (1964). Oscar Beregi Jr. would work again with two of his fellow guest stars, first with Danielle De Metz three years later in The Scorpio Letters (1967), and on two occasions with Wyenn--in the episode of The Girl from U.N.C.L.E. (1966) titled The Garden of Evil Affair (1966) and in the episode of Cannon (1971) titled Press Pass to the Slammer (1973).