K4 Kindle frozen at Tequila, power unresponsive

So I managed to get the Kindle 4 system at such a low level (namely, Tequila System Diagnostics) that the power button flashes green as if powering off then nothing. Still frozen. Is there any way that I could possibly do something not involving the power button, like unplugging the battery? :help:
EDIT: Normally, users must go to a menu item, so the power should have been unresponsive. Also, I managed to freeze it in USBnet mode, meaning that it won't function as an actual Kindle when plugged in. The five-way controller, nothing works.