At Siobhan's expression Kyle had to hide his face behind his notes in order to keep from laughing. Sam gave him a confused look and kicked him under the table. The pair of them went to making their Forgetfulness potion. Kyle, much too excited to pay close attention, and Sam of limited potion making skill, forgot to add only two pinches of mistletoe powder and instead each added two. The additional powder made the concoction explosive, and Sam was the unfortunate one to suffer the singed hair and blistering skin as Kyle nearly subconsciously cast Protego. His spell caught the worst of the explosion keeping all, but poor Sam who had been hovering over the potion, safe from the fire. 

"Go ahead and go to Madam Pomfrey's office." Slughorn waved Sam out of the class. "I'm impressed McCarthy, that was a powerful shield charm."

"Uh, thank you sir." Kyle resisted glancing at Siobhan because he knew if they made eye contact neither of them would keep a straight face. Slughorn waved his wand and the mess disappeared. 

"If you think you can finish a fresh brew before class end I'll not give you a zero." Slughorn waddled back to the front of the class. Kyle glanced at his watch. If he could get the resting period down to just 40 minutes instead of the required 45-60 he could finish in time. Kyle quickly started brewing the potion again. Without Sam there it went slower, but much safer in Kyle's opinion. While he brewed he ignored that everyone else in the class was turning in their potions. The Gryffindors saying snide remarks as they passed him, Kyle chewed on his thumbnail to distract himself.