Teaser 2 (I don't know the actual order that these came out in, so forgive me if I have them swapped. I chose this order based on how I felt they flowed better from the first) is a scene given to us in the first teaser, only with a slight little twist in that her hug (and acceptance?) is slower and more hesitant than the first time we saw it.
Teaser 3 is one of those times I really, really, really extra super hard wished that I understood Korean. Our OTP is standing outside of a hotel with dramatic music and fireworks blazing. He swallows loudly and she blinks. We definitely get the "something's about to happen here" vibe. I know I got all twitterpated....
But here, don't just take my word for it - go check them out for yourself. Maybe your Korean is better than mine and you'll get a better idea as to what is going on. ;)