Visible crew/equipment: Shadows of the boom, crew, and cameras can be seen moving about in overhead shadows during varied scenes.
Revealing mistake: For a prison governor/warden, Mrs. Davidson (Erica) would presumably earn a modest upper middle class salary. Yet here she is on the phone, in the foyer of her home, wearing an elaborate house dress, surrounded by very stellar furnishings. But then she answers a knock at the door, and opens it to reveal a very ugly vertical striped wall mere feet behind her visitor. Obviously indicating that she either lives in a dim-tenant or low-scale apartment, or this scene was shot in-studio.
Frances Harvey: You'll get yours, ya fat dyke bitch.