Nice. I understand this is a demo, but wanted to point something out. If you put your docker on top of the door you can hide the rails and docker much easier as it will all be above the doorway. I love seeing logic/rail examples posted as they can be very helpful for newer players. Thanks for posting!
I'm gonna take the opportunity of giving tips to make Doors more visually pleasing: You could even have the Rails in a completely separate place and, from the docked entity, build the Door on its desired place (making it effectively a floating Door). Now you have a Door with absolutely no Rails on the sides and no Docking Module attached to it!