Severus’ brow furrows as he thinks. After a few minutes, he whispers, "Of all the places to go to get a potion, why from Hogwarts students?" After another minute of ruminating, he continues, "Why these students were chosen is pretty obvious. They’re some of the few who are dumb and cruel enough to agree. I suppose if an important person were suspected of spiking someone’s drink with poison, Hogwarts wouldn’t be on the list of places to procure it from. Nobody would suspect them to get it from some impressionable teenage wizards."