"I'll defer to your judgement in this case, then," Ambrose said, as if he was doing a Macmillan a favor. As much as he enjoyed detentions and docking points, letting this one go was probably in his best interest, as he'd rather the Slytherin go unpunished if possible. And it seemed to be.
Smirking at the Ravenclaw who was still looking rather scared he gave him a stern, "Just watch who you shoot spells at, because next time, if it's me that catches you, you won't be so lucky." He nodded at the Slytherin as well. "We'll talk more back in the common room, too," he said, this time with a much friendlier tone.