When Aron had stabbed Joe, he had done so with two things clearly in mind. First, that Joe could easily be saved from the wound, and second, that it wouldn't cause permanent damage to the point where it would affect his fighting in the future.
Aron's intention was only to make Joe feel real fear, the kind of sudden, agonizing shock that might finally trigger his power. Aron himself remembered when he used to feel real fear; in his own brutal training, he had been stabbed a few times and had even worse things happen.
The thing was, everyone's reaction to certain stimuli was different, and now Aron felt like he had done something drastically, irrevocably wrong.
"I apologize, all of this was my mishap! I went too far!" Aron said, dropping onto his knees with his head bowed to Max. The gesture was dramatic, but utterly sincere.
