Erin should have made her move sooner! I don't think this is gonna have a happy ending...
Remember that Erin is back in Tackleford asking Amy how to attract The Boy. I'd expect that that advice is not going to be very good for the situation.
Maybe Erin will have tarted herself up to attract The Boy, and will wind up making a fool of herself? Maybe she will end up attracting The Boy to her instead, and Esther's dark side will come back out?
Maybe Erin will ignore Amy and instead simply get all pouty when The Boy and Esther get back all grinning like idjits. Or maybe one or both of the new happy couple will be eaten by the landshark thing?
Or (and most likely) John's thought of something far more strange and awesome than those fairly predictable outcomes.