Kyle caught on, Yvette was the mudblood Siobhan had mentioned. "I thought you were going to sit next to me." Kyle's voice was raised and he sounded hurt, "You're going to sit next that mudblood instead?" His heart raced. As he said the word mudblood, he let all the venom he had learned toward muggleborns ooze out into his voice. 

Professor Snape, who had just been about to step out of the classroom, paused and watched the pair. Kyle and Siobhan could have no way of knowing what was going through Snape's head. Kyle hoped though that it would be something that would show his treasonous ways.