There is an incredulous stare from Charles for a long, lengthy moment, his mouth actually opening in the face of Erik's words. Easy.

"Yes, this is easy. So very easy." The stressed word drops in the hiss of a whisper as his tone becomes momentarily frosty. Not that it lasts. "You don't have a clue. Not a bloody clue."

Neither does Charles, not really, not knowing what he's trying to voice. His lips clamp shut firmly, the skin around them turning white and suddenly, suddenly he can't be in this room right now. A thousand things are raging inside him and, and—

He grabs a hold of the door edge and shoves it back (which might elicit a slam against furniture or the wall), walking out quickly and determinedly.