Laladak doesn't want to take any chances, and ties the skulk up good. Before Oreus stuffs a gag in his mouth, he offers the skulk a biscuit. The skulk eats the biscuit, but finds it dry.
As the party climbs the stairs up to Keygan's shop, the skulk suddenly stops on the first landing (going up, second landing if you were descending), and starts knocking his head on the the southern wall (opposite the next flight of stairs) and then jerks his head up sharply at the empty iron torch sconce mounted on the south wall. (In the spoiler is the text I gave you when you first came down the stairs.)
The staircase descends another twenty feet before opening into a room. From this landing, you can hear strange sounds emanating from the chamber below, specifically chirping birds, rustling leaves, and cheery giggles. The landing itself is bare save for an empty iron torch sconce mounted on the south wall.