Mium did fiddle with the gate calculation somewhat, but more directly just interfered with part of the calculation. The gate had enough power to bring two people from Central to Malsa, so by simply inferring with the part that would have taken him out of reality, there was plenty of energy to bring his other copy back into reality. Of course, swapping out two humans like that wouldn’t work nearly as well, but for someone that can sync up various elements exactly, it’s far easier to catch a ride like this. This would have resulted in the gate having excess power (since one passenger is getting on half way through so to speak), but that doesn’t matter too much on this scale, as undirected mana is generally moderately harmless and quickly disperses.

This presumably left the F8 prototype in Central, which, of course, is what Mium intended all along. Arron was wary of leaving Mium in Central, and Mium would prefer to send Arron back to Malsa, so this worked out pretty well for him in addition to retrieving his other copy.