“Aren’t you going to stop me, Emiya-kun?” Tohsaka turns back to me at the door. I reply with silence.

“So you won’t mind if I kill Sakura?”

“I have nothing to say. But if I can take your place. I will.”

"No. This is my role. I can't give you this role."

Tohsaka opens the door and disappears inside.

"I'm surprised. I thought you would stop her. Hm. It seems you are determined. The Holy Grail War will now return to normal. This is a bit disappointing, but I am looking forward to the end." Kirei says.

"What's there to look forward to? Are you predicting who will win?"

"Predict? There is no need to predict. You will win. Since you have cast away Matou Sakura, you will use any means possible to kill Matou Zouken, Ilyasviel, and Rin. I am saying I am looking forward to how this will end."

"Why? I won't fight Tohsaka. There's no reason for me to stop her, even if she's going to obtain the Holy Grail."

"You will fight her. You will be forced to fight her when you find out about the true identity of the Holy Grail. Having killed Matou Sakura, Rin will go mad unless she obtains the Holy Grail. She will try to win for her belief and you will try to destroy the Holy Grail for your ideal. You two are incompatible with each other now. You two shall act out the final stage of the Holy Grail War."

The priest leaves the chapel as well. The room Sakura and Tohsaka are in. He knows what happened there is already over.

"Are you saying I will remain until the very end?"

"Of course. You are Emiya Kiritsugu now. There is no way you cannot win."

The priest has left. The only one in the chapel is Emiya Shirou, with a mind of steel.

The priest’s words are true. I will continue fighting, defeat Zouken, Illya, and Tohsaka, and destroy the Holy Grail. That is the end of this war. That is the responsibility I took when I swore to be a superhero. It is the first price I have to pay to become my ideal.

There's no need to talk about the obvious outcome. Emiya Shirou will turn his mind to steel and become a superhero.