The Old man looked at Grey, hearing his words, he couldn't help but recall what Grey said to him when they were fighting. Grey warned him that there was something inside his body and used it to keep the Old man at bay who was worried. Grey then made him believe that he didn't put anything in his body with his reactions, and this made the Old man think he was tricked, hence he not only chose not to listen to Grey, but he didn't even take out time to check if there was even a probability that he was poisoned.
In the end, it was Grey's cunningness that made him defeat the Old man with nothing more than an injury on his shoulder. In fact, that injury could be said to be the downfall of the Old man.
The Old man chose to trade blow for blow with Grey, which turned out bad for him.
"Hehe." The Old man let out a self-deprecating laugh, he couldn't believe he was outsmarted by a youth. If he was told he would ever be in such a situation, he would never believe.
