The Doctor felt eyes boring into him and looked up, a bit irritably. "What's that look for?" he demanded.

"You really have changed," Donna said thoughtfully.

"Not that I've noticed."

"You wouldn't. Typical man."

"Atypical alien, thank you."

"Oi! Last time I try and compliment you, if you're gonna get all stroppy with me!"

The Doctor returned to his tinkering, hoping his companion might take the hint. Donna, of course, did not.

"How comes you just let the Adipose go?" she persisted.

"They were leaving, peacefully. I don't hold with shooting people in the back. And besides, they were just babies. It was hardly their fault."

"But weren't the Racnoss just babies, too?"

He sighed heavily and looked up, dark eyes brimming with ancient pain. "Donna, the Racnoss are carnivores, born starving. They would have swept across the face of the earth like a plague of locusts - giant, man eating locusts."

"They looked like spiders to me."

He yanked off his glasses and scrubbed his eyes wearily. "The point is, Donna, they would have wiped out all life on this planet. And I gave the Empress a choice. I offered to take them somewhere they could start over. She turned me down. You heard it all. You were there."

"Yeah, I was," she replied softly.

"Oh, what's that face for?"

"Your eyes, that night. It was as if part of you was already dead, inside. I think…maybe…if I wasn't there, you would have just kept on going, even if you died, too."

"And that's changed has it?" he asked carefully.

Donna scrutinized his face. "Yeah. I think it has. And now I know I was right. You do need someone. No one can ever replace your friend Rose, but you need someone."

"You are right about a great many more things than people give you credit for," the Doctor told her, quite sincerely.