"You're transparent. You keep lashing out at me, your denials and excuses for your behavior are giving you away. You're a terrible liar...," he looks to the boiling water, "and you're failing at making coffee."

Berserker shifts his weight a bit. He refuses to just let this go -- he can't ignore the weakness presented to him. Like a dog shaking its prey, he won't stop until he's satisfied with the ending.

"You care because you're not important anymore. My presence minimizes your significance. You've been pushed out of your comfortable spot."

Wrong or right, he's not backing down. Each word is delivered with cold indifference, detached from the situation. It really doesn't affect him one way or the other, but Waver's weakness can't be left alone. He has to learn from it. This is why he does this, not out of cruelty or malice, but out of purpose: force someone to confront what makes them weak. How they react isn't his problem -- whether or not they choose to deal with it only affects them, after all.