As soon as he took the middle ground, Andrew unleashed his skill that somehow controlled a boulder and sent it flying in the direction of Kevin. By the way Andrew was sweating, Zavier was sure that he had expended a lot of strength to unleash that skill but Zavier shook his head slightly as if saying 'What a waste'.
The reason was that the enemy that had a skin made of steel wouldn't even feel an itch even if the boulder managed to hit him up front.
Though Andrew only wanted to create a diversion big enough for the two of them to escape, he failed to take into account the fact that they didn't need to escape in the first place.
Kevin's teammates had a panicked expression contrary to his own confidence in his strength. They flung themselves out of the way of the boulder in order to avoid the aftermath of the collision of the boulder and Kevin's steel frame.