I think Grendal's meeting with Moridin and the big build up of Rand saying she is his intellectual superior, leads me to believe the whole thing is a sham. Grendal probably left the bread crumb trail to the forgotten palace and had a BA crony ready to do the compulsion on her behalf. She has been hiding in plain sight and has duped everyone. Moridin knew this and used her to trick Rand. I think Grendal succeeded. tGS beginning had to much of a LoC intro, except instead of Demandred receiving the orders in the beginning it was Grendal. Besides Grendal needs to live a little longer to give false hope to those who believe she'll reveal she the killer of Asmodean :o