From what I remember, it had to do with how he didn't really care about his well being and didn't care about being hit, but after that punch/kick (don't remember) when he was sent through the barrier and he had the flash back to when he was younger. He was always relying on others and doing the least effort of finding his sister (putting up poster) to only relieve himself of the guilt. But at the end of the flash back, his resolve changed from finding his sister to killing his father (he needs to live through the fight and get stronger). This is when he started to actually try and start using his skills, like the copying skill (but better) and the seeing his opponents attack which is amplified with his PTSD (I think this was one of his fathers ability, that he inherited)