Here is where this theory loses direction, IMO. From here, I would think that Tetzel would send someone, possibly Gaius, to try and destroy the PS. Seeing as how Rhue was never confronted by a high ranking Guided (AFAIK) other than Gaius, I must assume that Gaius is the one.
I don't think Gaius was under Tetzels orders to get rid of the PS, mainly because Gaius is just manipuatingthe guided. My guess is that Tetzel hasn't even gotten to that stage of the plan and is still building up rumors.