This episode was produced after "The Prodigal Son" and should be shown that way for two reasons; 1) Harrison reveals to Adrian things he had learned about the aliens from Quinn, and 2) the aliens learned about the Blackwood Project on "The Prodigal Son", which was how Adrian got involved here.
Philip Akin, Cedric Smith, and David Calderisi all appeared in the 1989 film "Millennium".
When Paul Ironhorse encourages Harrison not to give up he speaks of his experience during the Vietnam war. Ironhorse was played by Richard Chaves a veteran of the Vietnam War and joint author of a successful play on the experience.