Is it just me, or does it look like Bella's true power is that she can do anything so long as she can imagine it and honestly justify it as necessary to maintain the integrity of her mind?
If so, when she inevitably goes for revenge for Edward's death against the Volturri, she could very possibly just deprogram the werewolves and splatter the vampires because if she doesn't, they'll rip her to bits and then light her on fire and not stop until she's properly ashes.
At the very least, she should be able to think "If my body is damaged, my mind will be destroyed when I inevitably lose the fight; therefore, my body cannot be damaged" and become nigh-invulnerable physically.
I stated elsewhere that the shield isn't omnipotent. It also won't prevent injury that isn't mind-threatening. For instance, if she were broken into pieces and not set on fire, this wouldn't be immediately life-threatening, so nothing would happen. Then, by the time she'd be in danger of death by starvation due to being unable to eat while in fragments, she wouldn't have enough energy left that the shield could draw power. She can be killed by anyone who's paying attention. It's just harder for her to be killed accidentally or carelessly.
In the vein of the Harry Potter and the Methods of Rationality discussion threads this is the place to discuss anything relating to Alicorn's Twilight fanfic Luminosity. The fanfic is also archived on Alicorn's own website <strike>(warning: white text on black background)</strike>.
Previous discussion is hidden so deeply within the first Methods of Rationality thread that it's difficult to find even if you already know it exists.
Similar to how Eliezer's fanfic popularizes material from his sequences Alicorn is using the insights from her Luminosity sequence.
Spoilers for the fanfic itself as well as the original novels need and should not be hidden, but spoiler protection still applies for any other works of fiction, except for Harry Potter and the Methods of Rationality chapters more than a week old so we can freely discuss similarities and differences.
EDIT: Post-ginormous-spoiler discussion should go to the second thread. (If you have any doubt on whether you have reached the spoiler in question you have not.)