I seem to be stuck. I've found the runs I need to activate on floors 4 and 6, but I can't seem to get to floor 5 (or at least the correct side - I've found the secrets part of floor 5).

Can someone at least tell me which floor I find the entrance on? I've scoured floors 4 and 6 and so far no luck.

Thanks!

How embarrassing...and then I found it. After looking for what seemed like an eternity :)

It's a door on floor 4 - in case anyone else has a problem. Both floors 6 and 5 can be accessed from 4.