What I thought, is explained in the image. Not sure to what extent it "can be" even considered to be correct. Lets hope, I have understood at least a part of it.
Example shown in Image -
On Miller's planet, when an obj A travels for some units of time and it reaches the destination point Q. (P to Q)
So meanwhile on Earth, (if we consider that Earth is in different space/planes, hence considered as tilted line with reference to Miller's planet), to reach to point Q from point P, it would take greater time with respect to Miller's planet.
(As general understanding/maths is that, two co-ordinates on the straight line, when dropped on a tilted line [perpendicular to the straight line], will generate relatively higher distance on tilted line.)
So, assuming this concept, time spent on Earth is greater than that of the Miller's planet.