Watched the Rifftrax. Great stuff.
Just wanted to point out something about the whole "Fin is just a Janitor?" story element that people were hung up on. This is approximately what was said: "What did you do when you were based here?" "I was a janitor". I don't think the writers intended to imply that he was always a janitor, just when he was based there. But it's easy to see how the audience (including myself) took it as "I am a janitor".
The real reason he's a janitor is so that the call back to the trash compactor scene that comes up a few minutes later connects a little better, with Fin having a reason to know where a garbage shoot is.