It was on this mission that Itachi was stressed, he had to massacre all his clan at Danzo's request, and Itachi agreed to that because he didn't want war to happen.

When he was walking his steps stopped when he saw you standing in front of him, he knew you intended to stop him from slaughtering his own clan (uchiha), but he had no intention of being stopped.

"Go, I don't want to fight you, and I won't stop." Itachi said in a cold voice, he was serious but on the other hand he didn't want to hurt you.