My secret tunnel predictions were entirely accurate! Why do they always design these secret tunnels with numerous confusing turns and dead ends? After we get to a secret room in the secret tunnel, we do a weird 3D key puzzle (the many pieces of which were conveniently lined up right next to the door in question on a bespoke key assembly shelf) and find Deirdre, who somehow got into that secret underground room from another passage and promptly became stuck under a bookcase. Things are rapidly deteriorating in the making-any-sort-of-narrative-sense department, if you couldn't tell.