Hi there, As Keyria stated you have to explore the garden at the start of chapter 3 before the castle attack and take a walk. Doing so, you will discover some vines along the wall that are strong enough for climbing and will make a mental note to visit this place again at a less conspicious time. This will unlock the option to escape from the wardrobe and return to the garden when everyone is distracted by the carrier attack. Feel free to ask any more questions if you still run into difficulty. Good luck!