That's not our argument. She's clearly doing all of this cause she wants to, yes. However, she's also being used by the Jailer without her full on knowledge of it, and it's clear just by looking at the Jailer's description and what he's done throughout WoW's lore (Especially with the whole potential "dreadlord" thing).
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Well, she only had the choice between suffering in the Maw, or that. No one said it was a choice of her will.