[She's silent for awhile as she trots at Kara's side, not offended, just thinking about the question, what threads of the story to tell.]

When I was young, I did something...desperate. And it was the right thing, I believe that. A great deal of good came of it. But down the line it put a people in harm's way who would have fared better otherwise. I'm here for them.

[It's a very deliberate vagueness, the kind that discourages more questions, but gently, without her usual evasiveness. It's a very long story, with more of her heartsblood in it than she cares to spill just now.]