What i gathered was that he planned the fire with Claire in order to get the girl into an emergency, and then Claire would bring Joon, and he would save the leading girl, then boom *moment* and they would finally have their first true love's kiss, and then the dramaworld balance would finally be restored.
However, when Claire and Joon arrived, Claire said "this was not supposed to happen". Although, it was probably to seem like she was as shocked as Joon.
Am i making any sense? XD 10 minutes are seriously not enough for this, to explain everything properly. The episodes should have been a little longer.