When Sajid was talking to Sumbul regarding her Dad's re-marriage, I wonder if many people noticed the actual point where Sumbul got up and left.
Sumbul was responding to all useless queries of Sajid and told him that she wanted the best for her father, that's why she doesn't want a young bride for him. Then Sajid said that if she wants the best for her Dad, she should stop him from smoking and then asked Abdu 'U know why she can't stop him from smoking?'.
This is the point where Sumbul rushed out because it seems Sajid wanted to talk about how Sumbul herself smokes as well...
The housemates might not know that viewers are already aware of who all are smokers in this season and in any case it's not that big a deal. As shown in previous episodes, regressive minded people like Stan and Sajid seem to think that while smoking is okay for the males, it's very bad if females do the same.
So, in this discussion, not only did Sajid cause emotional distress to Sumbul by talking about her Dad's marriage but he also kind of tried to bring up the topic of Sumbul's smoking which distressed her even further..