I love the Shalka boys, so I'm thrilled to see a story about them! And plot, too! I love me some plot.

"Oh, so it's all about convenience to you. If you like, I'll just shut down that bit of programming, then. No need to care about me for you to function, is there?"

"Yes," said the Master. "There is."

Just like that, the argument broke. Alison found herself relaxing a little, even as the Doctor tensed, surprise etched across his face.

"What?" said the Doctor.

"Well, it wouldn't really be me, would it," said the Master, with a humorless smile. "If I wasn't willing to go to simply ridiculous lengths, just because I care about you."

I really liked this bit. The Master knows himself.