It would seems to me that the smarter course of action would be to stay in your position, to continue doing the right thing until you're fired, and to have a statement written prior to your firing...
And if it's important enough that you can't be discredited as a 'disgruntled employee,' distribute that statement to media under embargo until you're actually fired.
I can see it being more complicated for prosecutors/attorneys, but for other types of workers, I never really understood the concept.