You should never, ever murder an innocent person who's helped you, even if it's the right thing to do

Shut up and do the impossible!

As written, both these statements are conceptually confused. I understand that you didn't actually mean either of them literally, but I would advise against trading on such deep-sounding conceptual confusions.

You should never, ever do X, even if if you are exceedingly confident that it is the right thing to do

This sounds less profound, but will actually be true for some value of X, unlike the first sentence or its derivatives. It sounds as profound as it is, and no more. I believe this is the right standard.