"Ah, there, no, I can't help you. But even if I could, I would not.
"You see..." he frowns again. "This is difficult..." You get the feeling he doesn't think you would understand it if he said it as he sees it. "The very point of the situation the door creates is that you absolutely must not know what is behind it when you decide if you should open it or not. To know what was behind it would irrevocably affect your decision about whether to open it or not, and make the choice about the opening... well, worthless. In the context."