BDB shows that the main derivation of the Hebrew word selah is found through the fientive verb root סֶ֜לָה which means "to lift up (voices)" or "to exalt," and also carries a close connotational relationship to the verb סָלַל, which is similar in meaning: "to lift up" or "to cast up." The word סֶלָה, which shifts the accent back to the last syllable of the verb form, indicates that in this context, the verb is being used in the imperative mood as somewhat of a directive to the reader. As such, perhaps the most instructive way to view the use of this word, particularly in the context of the Psalms, would be as the writer's instruction to the reader to pause and exalt the Lord. 
Kudos Mike. You’ve tackled very well an extremely difficult scenario to explain. ie The truth of how an operating Scientologist’s mind actually works. They are not generally bad people, in fact they are quite the opposite for their intentions are based on good things. However, instead of expanding Scientology as they insist they are doing, they are actually shrinking and destroying it, and all the while the “help” button is in BIG NEON LIGHTS flashing away in their minds. They are so out of communication with life it stings!
Maybe the simplicity of why a Scientologist lies has to be lived and then rejected as lies before it can be understood. Like a lot of things in life one has to experience it first hand in an operating environment to grasp it. Intellectual understanding is not all that successful in the real world and favors ivory tower behavior. What strikes me as the insanity of a Scientologist, is the evidence. What must a Scientologist reject or suppress with their own sense of right and wrong when they see an empty Org (that they paid for). They lie to themselves just as much as they will lie to anyone else.
The more I see and read of the effect of Hubbard’s Policy letters by the ex-management and HCO departmental SO on this site the more clarity of the insanity and knee jerk reaction that Scientology was founded upon as a group. I happen to like some of the tech and like to see people unburden themselves of personal upsets etc but the operating climate devised for Scientology is extremely bigoted.
“We were put here to ‘glorify God and enjoy him forever.’ In other words, we were not put here to ‘do the right thing’ but to be in a ‘right relationship’ with God. We were not put here to ‘keep commandments’ but to conceive beauty, truth, and goodness. We were not put here to ‘take a stand’ but to walk in the light for the greater glory of God. Biblical truth doesn’t feast on fact. It feasts on relationship and revelation, which is why eternal truth is better communicated by the fictions of parables and narratives than the facts of science and philosophy.” (Leonard Sweet; 2nd ellipsis dots in the original)