Facing an open room with a brown door and a glass wall, turn to your left. You'll see an exit sign in the right upper corner in the hallway. Moving that direction, make your next right opening. Take a few steps forward down this hallway. You'll also see a red door at the end. Turn around right after the first door to the right. Once you're back into the walkway you came from, you'll see another opening just to the right of another circular wall pillar, head in that direction. There will be an open room with the door number 339 and some keys handing from the door, this is your final destination.