With such an extended offensive being his only option, time was on his side as well. Time enough to watch Metz's every movement. And while Metz would have the element of surprise by seizing the chain, he wouldn't have the ability to act upon it. The man grabbed the chain of his weapon, and pulled it towards him. An excellent strategy, and commendable thinking. This man was an excellent fighter, using spontaneity to keep the tide of battle in his favor. 

However.

With no emotional ties to the weapon in his hands, nor any fear that the weapon won't return to him after the battle is done. Shin released the chain in his hand as Metz yanked on it. With his footing already squared from halting his momentum, and his right hand already extended, Shin had the exact stance needed to deliver a crushing blow on Metz with no hope of his foe escaping. 

By accelerating himself forwards from the pillar in a high gravity area, he had thrown a massive amount of weight forwards. With that weight, Metz had also gathered an even greater amount of momentum. Even if he somehow took flight from his leap, overcoming the momentum would be a task that would be so impressive that it would actually leave Shin speechless. 

With his altered plan in motion, Shin lowered his right and and drew his left arm backwards sharply. Lashing his left arm out with his fist balled up tightly, timing it just so it would strike Metz in the center of his chest as the two collided. It might dislocate Shin's shoulder, but it would certainly break Metz' sternum. 

Shin could pop his shoulder back into place, Metz can't un-break a sternum.