After a night of drinking that Farla family decided to check out what was under the grate in their hall. The hole was just big enough to fit through, and what they found was an underground room with documents from the 1930s and an old, rotted cross in the middle of the room. It appeared to be a chapel at some point, of course, possibly when Catholics were persecuted in England and used the bunker as a hidden church. The house itself is dated around 230 years.
So I don't know if you covered this or anything, but in the scene in s4 where Stiles and Malia get locked in a room and kiss, I didn't really see anyone unlock the door. I thought this could have something to do with Stile's somethingness.