Exactly thats what i said Sam. You can see in my last sentence. Enough justification is not given to her thought process. How much is her love for arnav that depth is not shown on the face to the audience. See this scenario before she leaving from RM there should have been scene where she cries her heart out remembering the saansein rukh jaayegi and her love realization during kidnapping track and then the sibling drift due to her. Now she telling that even though i love you so much i cant see you in pain so i m going away. Then her conflict between her decision of going away from him and the emotions that are stirred by arnav these days. Wont you understand khushi then.