If it's Right Down Left Up Right. Just find the corresponding floor things that move you in the said direction on the minimap and follow them.
If it's the one with the giant floor thing moving you all the way to the wall that opens up. Every time you walk near one of those open doors one shuts and one opens. You can see which one is open on your minimap and go to it.
I hope you still need help. I went down there from floor 49 and did a quick run through it. You're going to have trouble with this game if you couldn't complete floor 11 just running around, but now that I'm there I'll help you out when I get a chance. I need sleep.