Turn so you're facing the grey wall with an open doorway on the right and a hallway to the  left with two paintings on the right wall. Turn to the left and head towards the two paintings side by side. You'll see you're in a bedroom. Turn back 180 degrees and head down the hallway through the open doorway where there are 3 stairs and then 3 more stairs in the distance. Just take a step through the open doorway. Just before going up the first set of 3 stairs, you're done.