1. We have read many articles, seen the promo and it was also covered in SBS that both Arnav and Khushi confess their feelings for each other but don't remember a thing.
SO my thinking is that Khushi is around there or maybe went to get some more bhang as as of the last time we saw her she was not completely out of her senses. She may persuade Arnav to have some more and so when they make their confession of love they dont remember anything.
2. We also heard a spoiler that Shyam might try to kill Arnav track
After they drink the bhang they might collapse in the bed together (no hanky panky) but Shyam will get to know this (maybe through Anjali) who happened to see them and he will begin his plotting to kill Arnav
3. Arhi Consummation Spoiler without intoxication
What I think will happen is that Shyam will try to kill Arnav maybe by altering his medicines and somehow Khushi saves him. Maybe he had a business meeting somewhere and Khushi going with him was a last minute thought or addition. She will be all flustered and will make sure nothing happens to him and when he comes to his senses he will ask "Tumhe kya pharak padtha hain" and she will say "Pharak Padtha hain" and will cry and hug him which will lead to their consummation
4. Lavanya Entry
After their consummation they will come back home only to find Lavanya @ home and this MU start all over again as Khushi will back off thinking Arnav and Lavanya have feelings for each other
5. Shyam MU Cleared
Khushi will leave the house, MU will be cleared and then Arnav trying to win Khushi back
These are just thoughts.
Please let me know yours