Remain idle

You think about telling her, but you also know that the other mistress is telling the truth. If you remain Mistress Elizabeth's subject, you will have this vibrator inside you forever. On the other hand, even if this other mistress is lying, she might just have a better fate in mind for you than this one. Whatever it may be. As you keep thinking, Mistress Elizabeth says "Good night, pet," and she leaves you alone in the room.

Bzzzzzzz!

The vibrator starts again, and you tense against the straps holding your body and the arms of the straitjacket. But in the end you give up, and you remain idle until the vibrations cease, and you can get some sleep again.