Unfortunately I don’t think this is true. Every 3D face is the intersection of a 2D plane with the upper and lower bounds of the 3rd dimension. So I think a hypercube “face” would be every 3D “plane” at both the very start time AND the very end time. Meaning the ant would need to immediately accelerate to light speed - so no time would pass - and then (otherwise) normally traverse the faces, wait until the end time, and then repeat the process in reverse (still at light speed).