I think when Veer said an Oberoi will destroy the Oberoi's he meant Anika. We all assumed that one of the family members will turn negative which is always the case.
Svetlana till now always tried to break the family. But Shivaye always was able to stop her. Even when she tried to break Shivaye through his family she never succeeded.
Shivaye is the root of the Oberoi family. Family and his brothers are Shivaye's weakness but if anyone hurts them, he doesn't break but the reaction is opposite. Svetlana tried by sending Shivaye away but she wasn't able to break them yet
But Anika, she is Shivaye's strength as well as weakness. Destroy her - Shivaye breaks. Shivaye breaks -family breaks.
Veer realised that and so he decided to use Anika and that's what he meant an Oberoi will break the Oberois. And Shivaye realised that Veer has realised he can break if something happens to Anika and he may also have realised that maybe Saumya is with Veer too but let's keep that aside for now.
Shivaye may not have realised that Veer's attack on Anika on Goa was not for destroying Oberoi family but getting Anika for himself...but his attacks on Anika proved that Veer will attack the weakest link in Shivaye and so Shivaye and Anika have probably allowed Veer to destroy Shivaye through Anika meaning they have planned it but making Veer think he is doing it.
Shivaye didn't drink the water it was so obvious he threw it away and pretended to drink an empty glass. He knew Veer was home so obviously he won't drink it.
Also that why the guys went separately and girls separately. Shivaye might have included his brothers in this that have to wait and see. And Anika may have purposely gone back home.
And also when Shivaye shot Anika there was no blood. How come..?
They had planned it before they left for the temple and not after Anika learnt the truth'...they already knew Veer was trying to hurt them...and now they are trying to find out why?