'door inside' is correct and usable in written English.
You can use the phrase when referring to a door that is located inside, as opposed to a door located outside. For example: "The door inside the office leads to the kitchen."
Fran opens the door; inside, the girls huddle within the gauzy tent, apparently hiding.
A despotic snobbery prevailed at the front door; inside, Studio 54 was a rowdy democracy, where individuals were reduced to mashed, polymorphously entangled bodies.
Mr. Hotchner walks along a stone path near a barn and down several steps that lead to an open door; inside, he points to a basement cluttered with a lawn tractor and tools.
They may not seem like much of an idea now, any more than the shiny Red Barn Door inside, which is nearly indistinguishable from the objects it depicts, and thus descend directly from a whole tradition of American art – Warhol's Brillo Boxes, say, or Jasper Johns's flags – but they remain catnip for collectors.
If you don't give ants a door inside, they'll be more likely to stick to outdoor areas.
On the door (inside) cover a piece of colorful construction paper or wallpaper with clear, thick tape.
These doors, made from corrugated metal, shield the glass doors inside, which means you can shut the house up like a little box when no one is there.
The resulting data is stored in an intermediate JSON format that encodes the position of each wall, the adjacencies of walls, and the position of windows and doors inside walls.
(If the barn is being built in areas where flies are a problem, hinged screen doors inside will help keep the flies out).
I opened the door, went inside and suddenly it hit me.
I gingerly opened the car door, slipped inside and pulled out.
