Basically the same thing that Iskander told Artoria.
or "what if I had done that"...Master.Stop being so conceited,We're all but heroes from ages.And I concluded that it would be the best for me to become a decoy.What do you plan to do with what-ifs and regrets at this late?And even now, I am perfectly sure that that judgement was not wrong.Supposing "what if I had done this back then"No matter how much you twist your head thinking of them, you'll never get anything from it.