Help with a mirror shot.

[Hive_Mind]

I've written a short 5-minute piece in which at some point the male and female lead stand in front of a brass double-door elevator, ideally each of them would be reflected in their respective door so that during their argument (more a passionate plea from one to the other) the doors would slide apart separating them. My problem is I wish to film it from behind so that you can see their faces in the doors, but how would I hide the camera?