In attempt to refute quantum mechanics, Einstein proposed a thought experiment where a box containing a particle is weighted before and after opening a small hole to release that particle. The precision of measuring the time and the energy of the particle can thus be known accurately which violates the uncertainty principle. Bohr answered by his famous reply that when the particle exists the box, the later moves to the opposite direction by an indeterminate distance to a new space-time value in the gravitational field that creates uncertainty in measuring the time. But this answer is not convincing at all, simply because gravitational metric is not included in formulation of quantum mechanics. So what would be the best reply on that thought experiment?