Severus doesn't move. He stares at her, dark eyes searching her green ones, the grips of potential magic not quite unhooking. He doesn't sense that she's lying or faking it and that doesn't make any sense but-- she's powerful and without deliberation in Legilimency maybe-- Merlin's sake, he's not going to do that.

His hand around his cup tenses, slowly. Nails press into synthetic ceramic uselessly. There is an air about him like a cornered animal.

Finally, barely above a whisper,

"Is this a joke?"