Wouldn't it be nice to have a little bit of descriptive text to go along with it? What does it look like and how is it concealed? What are the telltale signs of its existence - and how to describe those to the player? Where is the opening mechanism and exactly how does one operate it? Does the door make a noise when it swings open? I am sure this would make them more memorable and mysterious and would add to the overall play experience.
Just a thought...
