The Hallway under the Stairs

You decide to pass up the piano and go to the far door across the room. You pass through doorway and discover that you've entered a narrow hallway.

A few windows against the wall allow a small amount of sunlight to spill into the shadowy hall. Your eyes finally focus and you see that to your right is another doorway and to just ahead  is yet another path to take. Which way to go?

Ahead, further down the hall way?

or

Through the doorway to your right..

Or back into the room.