The fact that Lucy Gray is able to use Dr. Gaul’s snake to kill Treech suggests that she might be able to beat Dr. Gaul at her own game. At the very least, Lucy Gray can use Dr. Gaul’s weapons for her own purposes—and, like Dr. Gaul, she might not be trustworthy. Pay attention to the language Coriolanus uses: he wants to “keep” Lucy Gray. He still believes he owns her and has every right to her, if she wins. Her win doesn’t reflect on her, in other words: it’s Coriolanus’s win, and she’s his prize.