Edited Part:-- Why i am saying this , if u see Mihir was back in Delhi 2 days back and probably according to previous SBB/SBS segments, he was knowing Rinki's affair , so it maybe possible that somehow he could also be responsible in killing Rinki with any of the Iyer members be it either Ishita or Mihika as he knows that Ishita might sacrifice for that person if she comes to know . Also it could possibly be shown in FBs that Mihir and Shagun are planning all this to get back her position in Raman's life. Dont know what lies ahead as it seems to me that Shagun could well have told all this to Mihir and Mihir could have sent that lady to Dr. Manoj and Shagun showing that she found about but maybe since she shares the flat with Dr. Manoj , he could well have heard Shagun's conco sometime and that why he would have hatched a plan to uncover the truth and that could well be the reason that Shagun would like to leave the flat so she could now plan further and that is only possible if she stays away from Dr. Manoj and do the damage to IshRA relation.
Also Priya Ray said that some past relationship will indirectly affect Ishra that means either Mihir will go back to Mihika or Simmi goes back to Param, but i think Mihir-Mihika seems more possible and and as someone said that whom will Mihika marry --Mihir or abhishek as that is a twist , so probably then Mihir's truth will come out and at the last moment Mihika will back out . Let see what happens from here on.
Hope this makes some sense as it is making to me as of now, dont know what is going to happen.