i learned recently that this is a false premise; the frogs will get out when the water gets too warm for them. which imo makes its proliferation even more apt; it makes sense that they would, but we’ve so used to the narrative that we keep this factoid going without questioning it.
Unless you’re shot in the legs or your injury would otherwise impede you from standing, you wouldn’t naturally fall down.
However, movies and TV have drilled it into our minds that you fall from being shot to the point that we DO fall because we’re SO DAMN CONVINCED that that’s what happens!