Rose hugged the Doctor a sad look in her eyes as she also left the two lovers alone. "I know. And I know how it feels." To lose the one that your heart loved was torture. She had to go through it after Doomsday and when he had died thanks to an alternative time line. It tore at your heart and made you unable to move or do anything. And she also knew the fear of losing that person thanks to the Impossible Planet.