After falling down the bridge, there is an empty lantern to the `east`. To the west, there is a passage, where one can take the `ladder` down or venture into the `darkness`. Attempting to venture into the `darkness` at this point will result in being eaten by Grues.
Taking the `ladder` down, then traversing `west`, `south`, `north`, a code is obtained:
Chiseled on the wall of one of the passageways, you see:
............
You take note of this and keep walking.
There is also a can, which can be `take`n and `use`d to fill the lantern, which can then be `use`d to become lit, and which will keep away Grues.