With a sudden moment of downtime on your hands, you seize the opportunity to think things over. It really doesn’t surprise you to see that they’d want to return to Ponyville: they must be itching to get their hoofsies on whatever other macguffin they’ve no doubt got kicking around there. Intuition dictates that said macguffin is probably the Elements of Harmony, since their current powered-up state isn’t working quite as well as they’d hoped it would against you, and they knew it as well as you did.