There absolutely is a coordinate system like that, in the comic it would be the spirit’s coordinate system with them at the center. There actually is an absolute center of the universe and it is you and me, and everything else in the universe is at the center of it’s universe (depending on your definition of the universe). That’s what special relativity is all about, each thing is at the center of it’s own universe and you have to translate any measurements between coordinate systems.

All the comic implies is that a sprit doesn’t follow null geodesics, but that’s general relativity.