The way Stocke learns Vanish. He basically goads Heiss into spamming it in front of him so he can pick up on the basic idea, grabs the documents he was after to begin with and then uses it himself to escape the city.
When Stocke confronts Queen Protea, he doesn't even have to do more besides threaten her, and then ominously thumb his sword as though he would draw it against her, to get her to surrender and flee.
Stocke correctly guessing where the bearer of the Black Chronicle would go, then jumping to that node to prevent Eruca from being murdered is a particularly impressive moment, where one time traveller outwits the other.
Heiss finally realizes his role in the Golden Ending, and gives up his life to let Stocke live in his place.