The blue door is of course the rest room, or "head."
That would be the blue door, to your left, sir.
Oh, I'm over the other side of the landing there with that blue door.
Behind a blue door on the second floor, across the hall from the projection room, was the source.
It was a pleasant house with a blue and white door.
Sometimes, he opened the right blue door and the beautiful lady came out.
They went up the path to the blue front door.
He also saw the heavy blue door that led out to the parking lot.
Very slowly the blue door of the apartment opposite began to open.
It was just a hundred feet to the blue door.