Nynaeve didn't believe that the messenger's death was accidental (nor did anyone else, really, except those in charge of the prisoners.) Your excuse is invalid.



Right, I forgot that "why did a man Copmpelled to poison a prisoner poison a prisoner" is something you consider an inescapable plot hole, but an insane, pointless scheme requiring omniscience on the part of someone who has never displayed such powers is perfectly rational, the lack of a good reason why Rand's Compulsion was erased is perfectly rational, and the complete inconsistency in the narrative is perfectly rational.

Your speculation is marginally less credible than Light in the Night's The Mirror World Switch.