A Mysterious Door

Guys, there's some for real Alice and Wonderland wrong-sized-door foolishness going on in the shop this week...
We've tunneled into an alternate Bicycle Revolutions universe and before long the shop is going to have a whole new look, but what will it be? ANY GUESSES? What should we do with the mystery room? And what on earth is in there that the ginger bullet so enthralled with in this pic?
Comment below and maybe if you have an awesome enough idea we'll cry and beg the contractors to make it happen. All you can eat taco nook!