It was wiser to have one person standing away just in case the flailing and slapping were ruses.
It was wiser, and more of a precaution, but Trowa was younger even then himself now. Probably in better physical shape, too.
Swat the fist away. Grab the other ankle before it could kick. Flip him onto his stomach. Place knee in the small of the back with his weight on it, both hands secured by gripping them crossed at the wrist, gun holstered securely instead of held to the back of Ehmoi's head.
Muscle memory was a bitch and a half when you didn't want to silence everyone who saw you anymore.