Now assured that the lock has been jammed, the party proceeds down the narrow corridor, finally coming to the conclusion that though they haven't seen her cast any spells (as far as they could tell), she IS William's apprentice, and so probably can.
After a few minutes of discussion,they arrive at the split corridor.. the Caved-in (and then dug-out) corridor to their right, and the untouched door to the left, which radiates stronger Evil to Deirdre than the other way.