In my personal experience, it’s very rare to catch a comment/story while vouchable. Not sure how many flags does it take for something to be killed, but it seems like almost as soon as something gets flagged, it becomes a signal for others to flag it too immediately without thought (similar thing kinda happens too when you post a comment and the first vote is a downvote, it almost never recovers, even if it was a good comment, as the initial drop/greying biases anyone that sees it before they even read it)