When he's finished torturing Lucius, he goes to see his wife.
She is asleep, her mouth slightly agape. He watches her amusedly.
Narcissa Malfoy. Born to wealth and power, ill-equipped for discomfort.
He experiments with pointing the wand at her pale chest. Two words. The ultimate punishment for Lucius. Except, perhaps, what he did to the boy.
She stirs, and he decides that if she wakes he will kill her.
Yet she slumbers on. He lowers his wand. It is premature, in any case.
He stands to go. So you live to fight another day, he thinks. As do I.