Wokcus

Never mind - I figured it out. However, it does seem like that key is supposed to open door.

The mayor of Cotra gave me a quest called Nepharim Prisoners. I've located the prisoner in the Nepharim Fort. Just outside where they're held, I clicked on a cabinet that among other things contained a bronze key. The text said I took the key. However, when I try to release the prisoners, the door doesn't open (Difficulty 5). Is the quest bugged, or is there some other key somewhere that I missed?

Thanks