[Anger is something Ken responds to. Mainly because it feeds his own, so really they're almost creating a feed back loop]

THE PAST IS STONE! YOU CAN'T DO ANYTHING TO CHANGE IT!

[A tiny voice in his head is trying to get the point across that while you can not change the past, it changes you, but it's being very staunchly ignored by the rest of him. He's too busy thinking Schu is a moron and being angry]