Another (simple) option - Graendal has an Aes Sedai or Wilder Compelled in the palace. She Linked with them, wove Compulsion, passed the Link and escaped.

I just think there are so many ways around dying in that instance. Graendal is the only Forsaken that actively looked for angreal, and she seems to be the only one that can control her pride enough to avoid getting into a battle against all self-preservative instincts.