While you were doing THAT, I found a scrap of paper in the book I was reading. "You've read this trick a hundred times over in mysteries and mansions. A secret passage opened from knowledge under a guise of red. If you can't figure me out then pick up a book." I think I just got sassed by a piece of paper. It seems like the clue wants us to do something with the bookcase in the ship. Why is there even a bookcase here? Doesn't that seem out of place? Why disguise a door and then write a clue? I've confused myself now, probably best not to think about it further.