Gary was unsure what would happen once his HP reached 0, whether he would just faint and lose consciousness or if his System would really kill him off, but he sure as hell wasn’t willing to find out. It was a test that he might not exactly come back from. The high schooler was certain that no matter the consequence, if it wasn't for his Last Stand skill, he would have surely died to Kirk’s attacks. Driven by his fear of death, the Werewolf had put his all into that last punch.
His survival instinct had kicked into him, making him use every ounce of strength that had been in his body. The teenager had completely ignored who his opponent was and his personal relationship to him, it had merely become a fight to the death, the only options were either to kill or be killed.