All of the comments I've read on what to do once I enter the tower is to go to the nortwest up some stairs. The problem is, I don't see any stairs in the nw, and that may be due to the fact that I'm having a hard time getting through the seven by seven or so squares of conveyor belt. How do I get through it?
And I already saw the portal just to the south, but that only leads me to a chest.