Veena and Ashmit are the most insecure housemates. They can't take any kind of rejection. We've seen how they used to behave with Sara and accuse all others of conspiring against them and all. Ashmit cannot digest that he lost the election against Shweta.
These two were so wrapped up in each other that they did not realise that after MT has left, the politics in the house has gone down and. Khali and Dolly have become calmer and friendlier with Shweta and Sam and against Veena.
They have been resorting to cheap tricks like making ppl wait for small things like going to the loo, and then leaving the water running, or taking the biggest buckets and then wasting water for shower and all. Every time Dolly, being the fair-minded person she is, she has pointed their mistake out.
So Veena was only trying to take out the entire frustration of the day on Dolly. Ashmit and Veena also realise that they are the two people nominated by the rest of the house mates. so their behavior is only going to turn ruder and weirder.