Possibility who this third person could be Sahil and any other member but not kuruna for sure coz as far as I remember, pia , jigaysa and kurana had a table table and remember pia was all acting about loss of memory and rapid firing questions about her past and all that crap if kaurna is the third person the question is why would she be acted stupid infront of them two I don't get the whole concept its for sure that its not kurana or may be the created direction has made the stupidest mistake and thinks that the audience are fool opseeeeee