“Because matter is, for Aristotle, a substratum in which a potential to change can be actualized, any and all potentiality must be actualized in a being that is eternal but it must not be still, because continuous activity is essential for all forms of life.

“This immaterial form of activity must be intellectual in nature and it cannot be contingent upon sensory perception if it is to remain uniform; therefore, eternal substance must think only of thinking itself and exist outside the starry sphere, where even the notion of place is undefined for Aristotle.”   Wikipedia, article on Unmoved Mover

So, we see that unmoved movers still are in motion. No physical motion but mental motion. That is why there cannot be static thetans, without immaterial, spiritual motion they would cease to exist.