Daniel stopped even pretending like he was still paying attention to what the book titles were, his eyes on John as he worked at the shelf. John really must have known the Doctor much longer than he had, or as the Clone Doctor implied, definitely traveled with him, because these were things that sounded like they came from someone with more intimate knowledge of the Doctor. Which... could amount to anyone else too. In the grand scheme of things, Daniel hadn't known the Doctor long.

The Doctor always seemed an oddball, friendly, intelligent, harmless, and generally unphased by life. When Daniel tried to press him on things, the Doctor tended gloss over it, or better yet, get distracted, half the time conveniently, Daniel thought. He didn't seem to open up.

John was blunt, critical, but if that flicker of memory he had was anything to go by, being brutally honest with him too. Daniel couldn't think of any good reason to destroy an inhabited planet. He was still having a hard time believing the Doctor was capable of mass murder.

"I find it saddening, actually," Daniel said. Not funny at all, even if he could see the neat analogy. "I can't imagine getting to a point in your life where you have to surround yourself with people to forget being guilty."