I personally think that the phrase is more of a sarcastic way of saying "press on until you persevere", encouraging one to not let anything get in the way of their progress; a way of saying, carry on with what you need to do as if nothing can get in the way & stop you from getting to where you want to be until you finally get to where your going. A way of "blocking out outside inferences that would impede your progress. I don't use the phase in a "literal" sense.