Today, after eight months, she does.
She makes sure that Sherlock and Tony are both awake, finds that they are but do not want to join her in the bar today unless she finds something interesting, checks her coin supply and finds it sufficient, and steps through.
Bell continuing to be dead was more unpleasant than the amount of pain required to make her stop. And Sherlock could not be quite certain that there wasn't a time limit involved, that any second spent tuning her masochism and experimenting with Tony to find a more pleasant delivery method might not be the particular second that carried her out of reach forever.
Dealing with Coin is urgent, but not urgent on a scale of minutes. They can stand here hugging each other and crying for a little while longer.
"And we wouldn't be able to figure out who else was in on her plan to nuke a perfectly nice section of the ruins of Europe so easily, either," says Bell.
"Moon," says Bell. "Public trial for her and her accomplices. I don't know if we can get her to admit to anything, and of course whatever vid I put out the smart people will know I could've magicked no matter what happened, but it'll go some way towards not making it just look like I'm picking on a rival for no reason."
"I suppose so," says Sherlock. "And in case of future unpleasantness, I think we should design a more comprehensive set of protections."
"I can't just be - physically invulnerable, or I won't be able to make coins in an emergency," Bell says, nibbling thoughtfully on her lip. "...Does Tony know what happened or did he just - you didn't tell him yet," she sees, looking.
Hugs all round. "So now I have to deal with the assassins - Coin and whoever actually planted the nuke and whoever else was involved - and also figure out a form of invulnerability that won't interfere with emergency coinmaking. I guess it could just go on and off at will like the regen does. Although Stella found it really useful to be able to make a hex unexpectedly that once, we're not looking at the exact situation that would make that relevant..."
"You could make yourself invulnerable but optionally able to feel pain from thwarted injuries," Sherlock suggests.
"That sounds... confusing, but I imagine I could adjust," says Bell, and she nods and spends a hex. "Is there any reason not to cover you two similarly?"