If it needs to be done, it needs to be done. No one person is bigger than the company.
I wouldn't enjoy doing it, don't get me wrong, and I realise that my own set of morals might get in the way (as with Herr's story, ideally I wouldn't fire that woman out of principle; she essentially made the company what it was. But then, would my own job be put at risk as a result? I can't do the job I'm supposed to be doing, and she's going to get the sack one way or the other).
It's difficult, to say the least.