Boss creatures (and maybe flying creatures?) can move between Pharoah's Hall and Mongol's hall, correct?
But Pharoah's Hall apparently is not a rope room, so does it mean that adventurers can't connect these two rooms with a rope?
The Creatures can find alternate ways that Adventurers can not find. Boss Creatures, for instance, know a secret passage between the two rooms that Adventures can not use.
You must find a Rope Room to place a rope in so you can connect the two rooms