It's a funny thing.
We use doors dozens of times a day but we don't' really think about them much.
We use them to go in... and use them to go out. Depending on which side of the door you are on it is an exit or an entrance.
They are a means of access, but can also be a means of denial by means of a lock. They can even selectively provide admittance, allowing fresh air in while keeping the flies out with a screen door.
When the weather is nice, we like to be outdoors... when it is too color or hot we like to be indoors.
Here we see a somewhat mysterious and hidden door that could be described as being “down and in”, which sounds a lot better than “being down and out”.