After the German bomb blows up hundreds of feet from the front gate, Baker states that the tunnel is caved in from the radio room to the exit. We know from previous episodes that the tunnel exit is just above the radio room and nowhere near the bomb site.
Klink: I want you to order the men to do voluntary activity of some kind!
Klink: Now why would a German plane drop a bomb here instead of enemy territory, huh?
Hogan: For one thing, it's safer.
Hogan: You know, if everybody in the Underground were as pretty as you, the Nazis'd be fighting to join?
Klink: There's something else you won't believe: when I was a boy at school, my teacher told me I had no talent!
Hogan: Well, they used to say the same thing to Rembrandt.
Hogan: I'm going back to my room and do some serious thinking about how we can get those maps to the art gallery. Hey, something to think… ah, it's ridiculous… still, it might… nah, never…
Carter: I think it'll work.
Hogan: It's crazy.
Newkirk: You're going to try it anyway, right?
Hogan: I have to.
This episode marked the twelfth of fourteen appearances from Jon Cedar as Cpl. Langenshneid.
Jon Cedar appeared in seventeen total episodes.
This episode marks the ninth of nine unrelated appearances by Bard Stevens.
This episode marks the fifth of five unrelated appearances by Karl Bruck.
This episode marks the sixth of eight unrelated appearances by David Frank.
This episode marks the sixth of six unrelated appearances by Victoria Carroll.
This episode appears fourth on the VHS collection's "Impossible Schemes" volume.