Why did Moses (peace be upon him) almost kill the man who sought his help for a second time, even though prophets are role models?

Moses, peace be upon him, did not intend to kill the Coptic man. Rather, his killing was an accident when he struck him to ward off injustice from him. The proof of this is his regret and his saying: "My Lord, indeed I have wronged myself, so forgive me." [Quran 28:16] On the second occasion, he did not intend to kill anyone; rather, he wanted to repel the unjust Pharaoh's man. The Israelite's claim that Moses wanted to kill him was merely a delusion of fear after Moses had chastised him. Moses' action was an exercise of his judgment in repelling injustice before his prophethood, and he is not to be blamed for that, because the infallibility of prophets occurs after prophethood and messengership.