Ulla is quiet for a moment too, considering that. Eventually, she says, "I knew I was swimming into problems. But I did it anyway. I just didn't realize how big the problems would be. I was in the way of someone else's ambition, and I underestimated the lengths to which he would go."

None of this touches the real reason she chose vengeance. It was never Roffe's betrayal that was the tipping point. It was Signy's.