Regulus considers this a small victory of sorts. If he had to spend this entire mission tense about the idea that he might try something to take over his mind, well, then she could spend it worrying the same about him. Of course, if he'd really wanted to, he could have just used the Imperious Curse from the start. But he really didn't want to give in to using something like that again, and, honestly, he'd rather just get this over with as quickly as possible so he could quit worrying about whether it was the right thing to be doing at all.

Mikoto, not as bothered by either moral problems or Slytherin instincts for revenge, just nods slightly. "Understood. We will continue to watch for patrols."