I've been thinking this. He's looking for that man, the one that knows everything to find his real path, the true meaning of his vengeance. He wants to make sure for himself that his vengeance is "meaningful" and he got a "point" doing that. My point is he can still going on rampage with or without that man. I dont know what's his actual problem. Did he hesitate? Not enough conviction to kill everyone? Still convincing himself? What can learning the truth serves his judgment by the way? Is he stalling from his own plan?