A person wants to achieve something. What does he / she do under normal circumstances?
1. Firmly decide what the goal is.
2. Search the various paths that would lead to that goal.
3. Weigh the pros and cons of each path and choose the one that has least amount of cons which would in turn give maximum satisfaction upon achieving that goal.
Sahir Azeem Chaudhary has a goal. And right now that's the only thing his mind is locked on. He is neither seeing the path that he has taken clearly nor weighing out other options. Agreed that he doesn't have time to do all that. But still, at this point of time, he is blind to everything except that goal.
By now it is clear that Arzoo is not and has never been a gold digger. It is also glaringly obvious that she has strong feelings for him. He is an intelligent guy so I am sure he has figured that one out, confession or no confession. So in a roundabout way, he knows he is going to end up hurting her at end of the day when this whole deal issue comes out. He knows but the knowledge at the moment is not registering. And if it is registering, he is ignoring it. All he keeps seeing is that if he gets her to confess then his vow will be fulfilled. The goal will be achieved. The fact that the path he chose is built on Arzoo's love and trust and his own deception is once again known but not registered. Hell, his own love is being trampled by his booted feet but he is refusing to acknowledge the pain. So locked on he is on the goal.
There is something else he is ignoring. The fact that the journey doesn't end with the goal. There is going to be an aftermath. Keeping aside the trail of broken hearts (including his own) and shattered trust, Arzoo is not some random girl. She is the daughter of his mother's friend. Their family is staying in his house. Alvira might have had her own reasons in bringing Nausheen and her daughters to her house but as far as Sahir knows, his mother likes Arzoo and treats her like one of her own. Once he makes her confess her love for him in such a dramatic way, then what? Is he thinking about that? Zaki is going to witness the whole pool scene. That means the door of his room is open while all this MTM and declarations are going on. Does he really think after that, he can just dust and go on as before? That getting Zaki married / engaged to Samaira will be the end? That signing the deal and fulfilling the vow is the end? What and how is he going to deal with the aftermath? If Kurti apa or Anam or Alvira herself bears witness to this confession or comes to know about it later, what is going to happen? Has he thought through that? Kurti apa and Anam may sling insults at Arzoo and brand her as characterless or whatever. But Alvira? She would use it to her advantage. She would want Sahir to marry Arzoo citing that he played with her feelings. Did he consider that? Is he ready to take that step? With Zeenat still in the hospital?
Sahir Azeem Chaudhary has closed himself off. To the path he is walking through and the aftermath. Everything including himself has taken a backseat until only one thing remains. - The goal.