"Um," said the Doctor, frowning, edgy now as he saw the look on Chase's face slide and slip, changing in ways he didn't really like from ways he didn't really like. Both disconcerted him. "How do you know that's what will happen? Have you been..."

He paused, then caught a glimpse of the desk calendar behind the counter. "You've been here before," he guessed, from the date he saw there.