Severus (who is also having regressions to when a Lucius was a [remarkably incompetent] prefect, due to being in the company of only these two people while being angry with Professor McGonagall [not Minerva, really, as it's entirely possible that she was declining-to-control less horrible Marauders] for things she routinely declined to do during his student years, but is more or less in control of them and therefore does not stick out his tongue), gives him a wounded look, and suggests, "Thaumatic archaeology would be successful topic. Or," with a thoroughly wicked look up at Rodolphus as he frog-marches him along towards the pub, "street performers. Although that would definitely come back to violence."