Actually, it’s difficult to say exactly without knowing what this scene was made for.
As I can see in the file it has a repetition of the same scenario with very small differences. All the lights are inside of the geometry and from outside you can only see a bit of the light coming out from a small aperture of the door in the “outside” scene.
By default, there’s no big deal with the normals as Blender treats all faces as double sided unless you decide not to.
As I see, the scene is set to work with cycles that specially only have problems with the back faces if you set your material to ignore the back faces… so, there’s no reason you could not do it.
What I don’t understand is why the scene is a copy of itself, inside and outside.