"But the lock is special. Every time it's locked, it re-keys itself to one of the many pre-programmed settings. Every girl in your office now has a key to your cage. But at any given time, only two of those keys will unlock you."
Oh no! That's why Bobbi's key didn't work the second time! But if Bobbi's key didn't unlock you, whose would?
Hayley kept reading Mistress Fire's words: "I can't wait until you come to me, T, hoping that my key will be the one to release you. I'm touching myself right now as I think of the terrible things I can do to you in exchange for testing it on your lock."