When Emma takes Killian to the Middlemist field to save Him their theme starts after he says “Emma” and she says “Killian” it is a variation on their theme though but I think it has a purpose. It seems to switch between Killian having this sad version of their theme(fear of what he would become, trying to get Emma to let him go) and Emma having these brighter notes(hoping to save him, trusting they can fight it together) “I don’t want to pay this price. I don’t…I don’t want to become that” “You won’t. You can fight the darkness. I can help you....we can do it together” is a clear example of my theory. :)