Scared now goto-san... Ha. Ha. Ha. Ha.

I’m confused why is he scared? I reread it over and over but I still don’t get it

He realizes that the mc is stronger than him. This is huge bc there’s a huge gap between Japan’s S class and Koreas’ S class (Japan’s on a much higher level). Also, the mc is a mage type which is odd considering that he’s that strong.
╮(￣▽￣)╭

Because he felt that MC easily had his life in his hands and that if he had not stopped his punch he would have died just then.

Thanks you guys I understand perfectly now! ٩(๑❛ᴗ❛๑)۶