Possibilities -
1. MM to blackmail Rudra, that's for sure. She will either ask Rudra to leave Preesha if he wants to save Sharda. She can even threaten Rudra that she will kill Preesha, that's it for Rudra he will accept it. He will hide it from Preesha for few days. Preesha somehow will get to know about it (through Saransh mostly) and then they will get together and expose MM and will save Sharda ultimately.
2. Saransh truth out. I don't think so Rudra will get time to read diary so soon as MM will be blackmailing him but we can slowly see him getting normal and soft, a change of heart may be.
He might just ask some odd questions to Preesha to see her reaction.
3. If Preesha is successful in saving Neerja, Rahul will decide to tell the truth as a gratitude. Yuvraj needs to be looked at how and what he does. It will again do or die situation for Rahul.
He needs to get to know that oxygen supply was turned off and his brain needs to process it as it could be Yuvraj.
I think Rahul will escape the accident somehow and will tell Rudra everything.
The family will leave the country of at least Delhi asap.
4. RuSha exposing MM, Sharda saved as MM never died. She might try to hurt Preesha but I hope Harish Jain tells the truth that time.