Failure
When Don left the house and went to work, Vanessa kissed him goodbye, closed the door, and then ran into the other room to get the camera. He downloaded the recorded material onto her computer and then watched it. But what she saw was not what she had expected at all.
All she could see was Don entering the room, but then his body was blocking most of the camera, so there was nothing else to watch. Knowing that the room was small and that there was no other place to put a camera, she knew she would have to follow him secretly somehow.