Zainab is currently being manipulated by her ex-husband Yusef Khan (Ace Bhatti), who stooped to a new low last month by crushing up pills into her food - causing her to overdose.
The mother-of-four has since recovered, but Yusef's path has been left open for more schemes in the weeks ahead as Zainab's partner Masood recently decided to divorce her - leaving her even more isolated.
Wadia told Digital Spy of the storyline's future: "Oh gosh, there's definitely more shocks and surprises to come for Zainab! The scripts seem to get darker and darker each time, and every time I open a new one, my jaw drops.
"The coolest thing is that I've just received scripts for two weeks prior to Christmas, and those scripts have already shocked the life out of me. So goodness knows what Christmas itself will bring!
"The scripts are page-turners. When you get those scripts where you can't wait to see what comes next, that's when you know that you've got something special in your hands. I'm literally thinking, 'Oh my God, oh my God, what's going to happen next?'"
Wadia added that while Yusef currently has an ambiguous quality, she believes his main motivation is revenge.
"I think that's the clever thing about the way Ace plays Yusef - you never really know," she explained. "Sometimes when I'm playing the scenes I'm not quite sure, and I only figure it out when I watch them back.
"I think what Ace does is really brilliant - it unnerves me both as an actor and as a character. I personally think that somewhere in there, Yusef has a love for Zainab, but I think his primary intent has to be revenge.
"That's what I think as Nina, but not as Zainab. I think Zainab falls in love with him, and she actually thinks that they could love each other."
Wadia is currently promoting her new film Four, on which she worked as executive producer. The movie goes on general release in cinemas on October 21.
> For loads more chat from Nina Wadia, read our full interview about EastEnders and Four
> Read more EastEnders spoilers and news
Watch Zainab's EastEnders character trail below: