My prediction: The Jailer will leave Sylvanas behind while he escapes with Anduin. Sylvanas will be angry and surprised by this before she’s killed by Jaina or Thrall, possibly Tyrande if she suddenly shows up. The good half of her soul will go into her body, bringing her back to life and curing her of her undeath. She’s our lead to wherever it is the Jailer went. She knows where Anduin’s compass is which will explain the zone we go to for 9.2.