Snape arched one eyebrow. "Mister Potter had been instructed to return to his common room and assure the remaining Weasleys that you were not in any mortal danger after causing a scene at the library. And I trust that you will have ample time to finish whatever assignment is due in three weeks’ time." He muttered something else about that professor being lucky because this might be the one time she would not write a foot more than was required, before nodding at Madam Pomfrey and leaving the hospital wing.