“why don’t you listen to what you just said in your head, and let’s start this conversation over from before going into it with the wrong attitude” is a more polite version of “the fuck did you just say? Start over and drop the bullshit at the door.”

And I wholeheartedly recommend using it if the occasion pops up. It’s not rude, not confrontational, allows the person who said the dumb thing to hopefully realize their mistake and brush it off without being directly called on it. Any supervisor that is worth working for won’t bring it up again.