Where does a fire go when it goes out? Does it go north, south, east, west, up, or down? No. It doesn't go anywhere. It ceases without remainder.
Reality is moments of experience not objects or entities. Moments of seeing, hearing, smelling, tasting, touching, and thinking. Nibbana is the cessation of experience. Parinibanna occurs after death once Arahantship has been attained. It is cessation without remainder. No more experience arises. There is no being that goes anywhere because there was never any being to begin with. There was only ever moments of experience.