River had a feeling it would come to this.

Being in the Doctor's body, experiencing what he experienced, feeling what he felt - it was all quite taxing. She was all too often overwhelmed by his simplest emotions, thoughts, or memories and it was becoming very taxing to keep her own feelings for him from bleeding through their connection.

Doctor, perhaps we should have a little talk?

She had to be so careful. This was like walking on ice, the slightest slip up could cause unrepairable damage.