I'd say Avi was right when he said that Arpi does whatever she feels like w/o informing him. As a result, I don't blame him for not 'caring' about where she is.
When Avi was exercising & BJ went to interrupt him, I was half hoping that he'd land that club on her head. Like Hanuman-ji did to so many demons.
I think that RV or no RV, the police could well put Avi on their shortlist of suspects, and really grill him, and maybe his friends. If RV returns to favor, Avi would be in bigger trouble. So if he's pissed, he becomes a romance killer w/ other people 😆 Maybe he could have said everything he did to Tanmay 😈 right in front of RV. But the last scene - did Puri tell everybody what happened, or just BJ?
Arpi'll probably be found downstream and in a coma. This part is a bit like PKCM (haven't read all the comments, so sorry if someone's already mentioned this) - she gets into a coma and disappears indefinitely, while the rest of the story goes on.
The day she re-surfaces, I hope she plays her tricks and shocks BJ & RV into thinking she's a ghost, and makes them confess to everyone - Avi, Tanmay, Shikha & Simple about everything they did. Then have them blown to kingdom come.