Also Pescado, if that was true you would get a big glitchy mess every time you use the tab camera to look inside an elevator, but you don't. This is not to doubt your awesomeness, but is true. All I can see is it is used for is to keep objects out of your way, but I don't need that since I constantly rotate the camera anyways.
Some objects tolerate this better than others: Elevators actually DO have visible interiors, and elevatorshafts are nearly entirely concave (being simple rectangular prisms), so therefore, you wouldn't see much (assuming that the interior faces are invisible). Objects that have more complex geometries will give you polygon soup.