Lyra was hit by the spell, but it wasn't very strong. However, it hit the shoulder that had been injured and it was still a bit sore. Her wand nearly left her hand, but she gripped it shortl before it would have flown out. But what had she expected from a first year? It was a bit unfair, a fifth year against a first year - but it was only a game. "Oh come ON Caesar, I bet you can do better than that! Expelliarmus" she shouted, so as not to wipe him right off his feet.