Our physical body is a temporary mask, an illusion that goes away. We are on the same plane and this is what matters. Plane 1. a flat surface on which a straight line joining any two points on it would wholly lie. "the horizontal plane" 2. a level of existence, thought, or development. "everything is connected on the spiritual plane" See? We are on the same plane and this is what matters.
Wherever, Kirk goes Spock will be beside him. As his First Officer, but, more importantly as his friend and fellow brother in arms. Because, Spock has lost too much already.