"Thank you," he said - and he meant it sincerely, as much as he had in a long time. He couldn't let it matter very much to him, but if there was one person he would rather not have think of him as a cold-blooded murderer, it was probably Minerva.
He doubted Draco would be equally grateful, somehow. But that was alright; he didn't get a choice. Minerva was on her way out, anyhow ... Which probably meant it was time to start making some advance preparations. Surely Draco wouldn't mind making himself useful.