If the man was just going to completely ignore the hooking of his foot around the back of Gonad's knee, and try to just keep powering through - then he deserved whatever happened to him. In the end though, Lysander had to wonder how the man could continually make himself stronger and stronger when the hall supposedly equalized physical traits and strengths to the same, base level. How was it that, in this place with its weak magic, that Gonad could be the base-line yet still somehow continuously be more powerful than his own base line allowed. It didn't really matter. That power was nothing without finesse, and Gonad was doing exactly what Lysander hoped. 

The headbutt wasn't meant to connect, really. It was only meant to give Gonad a sense of superiority, an idea that he was okay and that Lysander wasn't prepared to properly defend. The hooking of his foot around the other's leg was that defense. With his ankle pressing into the back of the knee, and his body being pulled - the result was simple. The force of Gonad jerking his body backward served only to jerk Gonad's leg out from under him with that same speed and force. The result would throw even the most capable of warriors off balance. 

He didn't expect it. If he had expected it, he'd have defended against it. Instead, he sought only to power through the attack and show his (somehow) physical superiority. Lysander just laughed. As Gonad's leg was pulled from under him, the torque and the twist of his own body unbalanced him and Gonad found himself laying on his back - with Lysander resting comfortably and unharmed on top of him. Meanwhile, his arms pressed against the others - whose likely fall at such force knocked the wind out of him. 

If their pyshical power was equal to Gonad's, then it was nothing now for him to break the grip and roll over even as he did - now within the guard of the taller man.