It isn't about whether or not you should pay her back, exactly. I understand your reasoning for doing so. But what would be enough to consider you even?

[ It isn't as though it's a case of "thanks for paying for my lunch, I'll get it for you next time". It's a far more complicated issue than that, and it's where Barnaby's curiosity comes from. The truth is that he's not sure he'll ever be able to repay Kotetsu for everything that he's done for him. Not that it's the most daunting prospect in the world. ]