Doing Time with the Big Bad

She accidentally transmigrates into a book as a minor cannon-fodder character, only to discover that her cellmate in prison is the book's great villain! He's so fierce, such a powerful thigh to cling to. How should she latch on? But the great villain clings tightly to the minor character's leg, pleading with eyes full of desperation: "Please don't go. I have no one but you." The next second, his eyes turn bloodthirsty, and he kicks her away. "Wench, you're filthy."