The person who came up with the phrase “quiet quitting” took the effort to incorporate alliteration, which made the phrase catchy. You’d think the author of the article 5 Signs You Are Being “Quiet Fired” From Your Job (shown above) would have put in a few seconds to do the same for its employer counterpart, but instead, they took the lazy route and simply replaced “quitting” with “firing.”
In my opinion, “furtively fired” — and its noun form, “furtive firing” — sound much better, are grammatically correct, and employ an underused word.