"Yes," he says dryly. "Upside down, with your grey matter splattered all over the floor."
Severus looks at him levelly. "If you are to continue as my apprentice," he says in a matching tone, "we will have a moratorium on such remarks. A student's duty is to expand and pass on what he learns from his teacher, and if he does not intend to fulfill at least half that duty, he is not keeping up his end of the bargain. In order to pass on his knowledge, let alone increase it, his life, soul, and sanity must survive long enough to do so."
He shrugs. "It's more a question of semantics." Quietly, "I managed to get out."
"By a year. No, not unless you want to ask Lucius."