an allegorical story
Trapped in a Luxurious Cage, a panic room movie, this is the first thing that comes to mind, But beyond its straightforward and one-line story, “Inside” is an allegorical story about man's expulsion from the Garden of Eden and his attempt to return to that peace and security.
By knowing this tip, one can easily understand the other details and obscure points of the movie, cause the rest of the meanings lie between these two lines.