I can't be sure about this because I haven't yet learned any parts for it, but I don't think "Stop!" resolves. Musically, this provides the same feeling as the lyrics at the end: "Make your mind up / What you're gonna do about us." The singer/speaker is left waiting for an answer in the same way that the listener is waiting for a musically satisfying conclusion.
In thinking about the song again to-day before writing this post, I also started wondering whether the title is meant to be similar to the Beatles' "Help!" They're both single-syllable imperatives followed by an exclamation mark. I'm not sure if the chronology allows for this though.
