Remus was jolted by Bill's shoulder and took a step back to catch his balance. The muttered word didn't pass by him, either. With a growl, he stepped forward and grabbed Bill by the shoulder, pushing him back against the frame of the door.
"Say it again," he said darkly. "So I can hear you. You haven't kept anything else to yourself today." He pushed against Bill once more and lifted his brows expectantly, wand hand ready.