When Khushi goes missing and Arnav will be searching for her - I think we are going to see a similar scene to the one where Khushi was locked inside the guest house and Arnav came to save her. Arnav was frantically driving to the guest house worrying over the fact that the place might collapse anytime with Khushi inside. Khushi on the other hand was crying over the fact that her life might end here and that her family members will miss her. We all saw how Khushi raged at Arnav when he saved her and she kept yelling at him and pushing him. Arnav reacted in anger and pushed her towards a wall and Khushi ultimately passed out.
I think we are going to something like this as well when Arnav finds Khushi. Khushi being Khushi might either cry her eyes out or she might be so furious she will keep pushing him which will lead Arnav to crab hold of her arms and we will see them both look angrily at each other. The anger will then slowly more over to love and Arnav will ask Khushi huskily how she could have thought that he will ever leave her. That how could she have forgotten the promise she gave him and they promise he gave her. I wont even be surprised if Khushi passes out from all of the pain and tension she has been through.
If you guys don't remember the first scene I mentioned here it is:
[YOUTUBE]http://www.youtube.com/watch?v=_FXn6wtbVY8&feature=relmfu[/YOUTUBE]
[YOUTUBE]http://www.youtube.com/watch?v=8mN2OSRGd2s&feature=fvwrel[/YOUTUBE]