I have been working on getting better at showing the reader, rather than telling. The fact that line worked so well for you is thrilling for me because I played around with it for awhile trying to get it right.

I'm pleased Hermione comes across clearly. As I wrote this I imagined a Sirius that had been watching her for awhile and has a pretty firm grasp of what is likely going on in her head. He doesn't want to engage in this dialog, he needs to stop and redirect the focus on him. I'm so happy it worked!