You’re indoors in the sense that you’re protected from the weather and the elements, and the cave could even have some kind of covering or entrance area that could be considered a door or doorway. People have built homes in caves.
Is caving an outside, inside activity?
Door don’t have roots, you’re thinking of a tree or maybe shrubbery.
Shrubbery! I heard some lot galloping by with coconuts looking for a shrubbery!
Ni! Ni!