Nossiter places the camera behind windowpanes, as if the viewer was spying on the action. Mirrors are everywhere. The camera will be on one of the actors, and another actor's reflection will be on screen. At certain points, it is difficult to tell whether or not what is happening is real, or a complete figment of Alec's imagination. It is a nice touch, and can represent any number of things.
Mirrors can signify the dual nature of the characters, both the duplicitous and the wistful.
It also represents the way Alec views his unreality through his own looking-glass.