This line is another puzzle. "Brad and Janet" would seem to refer to the protagonists of Rocky, except there are no androids in the movie to fight with. Perhaps O'Brien is referring to some other movie, which he like so much that he stole the heroes' names for his own play? But if so, what movie? There are no androids in Doctor X, and while there is at least a robot in Forbidden Planet, no one named "Brad" or "Janet". My best guess: As this stanza parallels the reprise that concluded the movie, O'Brien needed a line with the phrase "Brad and Janet" to balance the line "Darkness has conquered Brad & Janet." So, he figured he included a "Coming Attractions": "See Aliens Fighting Brad & Janet" But, then, as he tries to score it, he realizes that the meter doesn't work, so he makes a quick change, confident that no one will notice, "`cuz it's not like anyone's going to be studying this 20 years from now..."