OK, now you are facing the corner of a room. We will need to exit this room so turn around, the door is open. And, you will need to turn to your left, in the hallway, there is no other way, and inmediately to your left again so you can take down the stairs. And once you have reached the lower level you will need to turn to your right and you will need to walk straight forward until you step just in front of the black door that is closed, and this is going to be your end.