In the end of the last episode S09E08 of Doctor Who (2005),
Clara's duplicate villain Bonnie threatened that she would kill real Clara if The Doctor doesn't reveal which box would unmask the Zygons across the world. After The Doctor said that it was the blue one and Bonnie opened the box, she turned mad and demanded to bring The Doctor to the Black Archives. And then, The Doctor overpowered Bonnie.
My question is:
Why didn't Bonnie continue to threaten The Doctor over the phone that the real Clara would die if he doesn't tell which button would unmask the Zygons?