The Doctor sighed softly. "I'm afraid I'm at a loss," he confided. He felt he could trust Donna with that, and that she wouldn't panic at the revelation. "Since that... well, little oik, as your Doctor so elegantly describes him, won't even tell us what happened to break her... I'm doing what I can to get to the bottom of the problem, but I don't even know where to begin. Yes, the matrix is broken, but I have no idea what could have caused that."