as far as i know he himself did not know who the guy is and he confessed it to kasturi..
split personality just cos he was a bit aggressive in yesterday's epi and i find it natural for a person to react this way in one day he is accused of killing shivani,get beaten by his best friend and lastly his college friends making pranks they did in the past with kasturi..its this past which he hates that has made him so bitter in his behaviour yesterday but that does not make him a person with split personality..
i'm sorry reading your pov it seems by hook or crook you want raunak to be the bad guy and out of the story .