Friends
I kinda thought that's how it worked. You turn off all emotions, not just the 'good' ones, right? And yes, no argument on Katherine. As for how they work, I've seen two instances and only one in person and...it's complicated but it isn't literally a self-destruct mechanism.
I know. And I know the choices I'd make because there have been times I've had to do so. That doesn't mean it's easy for everyone else and I don't expect it to be.