We surely will come to know since when She has started walking. But it will b utterly illogical if the makers will show that she is able to walk since the day Riddhima has arrived. It will b a dumbest thing of Riddhima that she cannot find out that she has no ailment.Either Riddhima is really not a phsyiotherapist (its a lie as well) Or Cvs are dumb. They cannot show that a girl is paralysed and the entire family is unaware of it.
Vansh being unaware of it will b the other dumbest thing. Its clear that Siya is his ally and secret keeper. If Siya was able since the day 1then the entire growth of Riansh lovestory will b doomed.
The most plausible theory
Anupriya pushed her. She fell from the stairs. Vansh took Siya to her Room and they both discovered that she is alright. It was Vansh who stopped her and ask her to keep pretending. In precap Riddhima tried to expose her but Siya was fearless unlike Ishani Or Aryan. She challenged Riddhima to prove herself innocent.Hence it will b a way more logical thing to show that it initially was Vansh and Siya 's idea to keep an eye on Riddhima,to keep her protected and to vigil her where about.
Later Vansh revealed his truth as Ragini was gone. He was emotional and he at that point had realized that Ragini is lost and hence he tom the leap of faith and told everything .Siya was obviously unaware of the fact or may b she is aware i am not sure of it.
It was the same day when Vansh got the cctv footage and Riddhima get to know of Siya. So again there will b a communication gap where both will hide their individual truth from each other. Siya must have told about Riddhima 's involvement to Vansh if Riddhima would have not catch her red handed.
Since Kabir is lying again that he has lost Ragini and Riddhima in a given situation will obviously will trust him. To her Ragini is missing. She is a impulsive woman who concludes things very fast so she must b thinking that Siya has kidnapped her.I am still relying on my intutition that Siya is a well wisher of Vansh.But her ultimatum and anger was totally justified to Riddhima and I still think Sia is a matured girl who believes in giving chances rather than reacting agressively like Ishani.
Riddhima seriously is,in a very deep trouble as fate is being unfair to her again bcoz both the cctv and Vansh 's ally Siya will testify agsinst her. Really feeling bad for Riddhima as the girl has lost her dearest friend and Siya was very angry to her.