During the class trial, everyone was accusing Kokichi of being the culprit. However Kokichi later said that it was Gonta who had murdered Miu, Gonta then protested by saying he doesn't know and that he has no memory of it. Kokichi gets mad and yells at Gonta to make logical arguments to avoid any accusations. Gonta still didnt understand and was tearing up thats when Kokichi yelled something that made him cry

Kokichi: I'm sick of you saying you don't know! God, why are you so dumb?!