I'm in Eastwick's Grand House trying to get past a room with a patrolling guard and a servant, who are having a conversation. On the other side of the room is a secret entrance in the form of a bookshelf. There's a bird in the corner on the right and pieces of glass in the corner across.
I tried to sneak past following the guard's footsteps, but the servant is looking at the bookshelf almost constantly notifying the guard when I try to open it.
How do I get past the room undetected?