What if Ahsoka lived. . . but agreed to turn to the dark side?

What if Ahsoka lived. . . but agreed to turn to the dark side?

I was sitting in my car eating lunch wondering what happened after that door closed on Ahsoka and Vader. If Vader spared Ahsoka it kinda cheapens the events of ROTJ. If Ahsoka managed to escape it kinda makes cheapens Vader's power. But Ahsoka told Vader she wasn't leaving Anakin. What if she means that she would be willing to turn to the dark side to be his apprentice?

Just asking the question wrinkled my brain and broke my heart. I refuse to believe that Ahsoka would turn but thought it an interesting possibility.