Severus opens the door, looking very tired but much calmer, the occasional small muscle going into a brief spate of ticcing under his skin. The rate of this will slow over the next few hours, disappear entirely within two days, and if Sirius catches one of the spasms he's really in for it. Seeing Lucius standing there, waiting, and slides, after the first surprise, into a perfect, wary stillness. In another setting, he'd be disappearing into the wall behind him. He clearly expects to be upbraided, does not intend to apologize, and is dragging his new, weary calm up before him like a glassy deflecting shield.