[ There is less barely-restrained disgust radiating from Severus this time. He still looks like he's not getting enough sleep-- or maybe he's just always that ugly, and dim lighting is neglecting to do any favors today.

He's holding a glass laboratory flask; the contents are pale blue, and when he hands it to Charles as he steps inside, it seems to radiate heat. ]

For the record, [ he begins smoothly, ] I do not anticipate any ill-effects, but I know how wizards and to a large extent how muggles react to potions. I have no idea how a mutant who's gone and taken a hammer to his genetic code will react.

[ He could say it colder. Go in with something sharper meant to get in under his skin. But Severus says it plainly, pragmatic. ]