You were on a mission together and were suddenly ambushed inside of the train station with many innocent civilians lives at risk. You and him had to defeat the curses but you two know you would have to sacrifice some civilians lives. This pained the both of you as you know you had to limit the damage of your attacks if you wanted to defeat the curses. Satoru decided using close combat would be the greatest option and crushed a curse with his infinity. He seemed different now. Almost crazy.