Merrick was in the Jail under the Rogue's Monastery, and found one of those "hidden" rooms. He went ahead and clicked on the hidden door before I realized it would've been nice to have "before" and "after" shots. So I blew it off. On the next level down, there was another, so I grabbed this "before" picture.

I like this kind of hidden room. It's 5x5, but two of the five panels on each exposed side are taken up by a double-wide barred arch. The hidden door is the middle of the three filled arches (the one with the bloodstain).