digitalbusker quoted The Well of Ascension by Brandon Sanderson (Mistborn, #2)
The impossible has been accomplished. The Lord Ruler -- the man who claimed to be …
Content warning Spoilers for Mistborn: Secret History
It soon became too dark even for Mistborn eyes, and she had to light a lantern. When she did, she was surprised to see that her footsteps weren't the only ones in the dust. Apparently, someone else had been haunting the corridors. However, whoever it was, she didn't encounter them as she walked through the hallways.
— The Well of Ascension by Brandon Sanderson (Mistborn, #2) (73%)
I think that was Hoid on his way out after beating up Kelsier in the Well.