Here's what I managed to get out of the timeline of the Shivika scenes in the epi...
In the beginning, Shivaay was genuinely upset with Anika even during the ramp walk...it wasn't an act...he's hurt and doesn't feel like talking abhi...so that contributed to Anika feeling more abandoned since he was barely even looking at her...so then she also got upset and bol diya ghar nahin chalegi...all the while hoping that he will react and say tumhara ghar kaise nahin hai woh? But he didn't...so she kept getting hurt and then more upset and decided to walk away after all.
By that point, Shivaay was probably in two minds...1) yeah they gave him the more noble reason of protecting her by not taking her home to face Bua's wrath...lol...and 2) He was upset by her saying stuff like "mera ghar nahin hai" too I feel...he was clearly struggling with having to watch her walk away...he was upset, even though he was turning his face away or looking down, he'd invariably turn back to look at her too.
They specifically showed both Shivika getting FBs of the reasons for their MU during this scene...Anika remembering the fake wedding, the image of which still pinches her even if it was a fake one...and Shivaay remembering the CCTV footage of hers...even though neither of them believe the other actually did that, the IMAGE is still lingering in their mind as hurt.
Then later on, when OmRu confronted him, by then Shivaay's mind had cooled down a bit I feel and he had rationalized more that this playing into Bua's hands was so pointless and they both need to get out of it...but first he had to catch Bua...lol
Then when Pinky woke up, she clarified that Anika never really filed the complaint...even though by then Shivaay had cleared that he doesn't believe she did it anyways...so it just became a clarification for the sake of it...as if what his heart had really told him turned out to be true after all.
All in all an interesting turn of events...we will get more clarity about their mindset in the rain scene I think.