Camera operator in the shot

In the scene where Rachel Weisz's character has just slept with the photographer she's having the affair with, you can see the camera operator's reflection in the mirror. He's squatting down behind her as she's sitting on the bed. He's just inside the right side of the frame. He's there for a few seconds, before he reframes the shot.

Did they not have another take they could have used? I find it hard to believe that nobody noticed this on the set.