what the fuck? Why did he fucking did that to haruki aghh now I feel all messed up

to make him unconscious I think?
So that he won't see him kill the last bully idk

i've thought of that too but isn't that like too cruel?

I mean, he also gave him a pretty good alibi. If a teacher finds you locked and tied up in a building, it's hard to argue that you've been murdering your last remaining bully at the time