Undiscovered spooky action at a distance to what? Even assuming you can shuttle momentum around from particle A to particle C that is substantially distant, wh

Undiscovered spooky action at a distance to what? Even assuming you can shuttle momentum around from particle A to particle C that is substantially distant, what exactly are particles C? Does the EM drive choose the distant particles to transfer momentum to on the basis of what would be the most convenient for the experimenter? What is the mechanism by which putting microwaves in a funny-shaped container creates a momentum-transfering bond from that container to unknown other masses? Does this totally unexplained effect have, you know, a range? If so, is that range remotely realistic? If so, we don't actually have a reaction-mass-less drive, do we? For bonus points, answer all these questions in ways that do not create a privileged frame of reference and thus break special relativity.