Surviving Triple Sword is possible if you're a tank, which Naoto isn't. Beating Hiro with damage is possible if you're an excellent fighter or high class mage, which Naoto isn't. Overwhelming Hiro with status is possible if you accurate enough, which Naoto isn't. Miss Shirogane has a lot of 'maybes' and 'coulds' in this fight with her chancy instant death fighting style. Giving Hiro a single crack at attacking is suicidal enough, but a second and third try? Well, Naoto will soon learn the folly of challenging one of Heavy's best fighters with nothing more than a hope and a literal shot in the dark with her instant death magic.