The thought process on this is to give an added measure of realism to choose a door connected to some structure in game as your base.
Example, the Overlord badge an exploration badge in Grandville is on top of an Arachnos beach bunker.
I think going to the door as a normal click as to open would give the option to choose this as the entrance to "your" base if you so desire.
Obviously this couldn't be just any door as some are used for missions. But, still a vast majority of structures are unused so there would be alot to choose from.
Not only can they be exterior doors but, they can be interior ones too. Example an unused door in a police station or office building, sewer section, etc.