If a dependent marker word is used, the clause cannot stand alone as a complete sentence. For example: "If she leaves" = not a complete sentence. If an independent marker word is used, the clause can stand alone as a complete sentence. For example: "Therefore, she leaves" = a complete sentence.
I would say this would classify as a downward comparison as the person is talking about Mark who has a poorer job situation than him and this could be used to bolster the speaker's ego or to knock poor Mark or could just be an observation.
