As a practical matter, at mudcat it is virtually impossible for the "last person who posts" to "kill a thread."
The reason for this being impracticable in reality is the very large number of persons who may read (part of) the first post and then jump immediately to the end to post their "contributions" - without ever looking at any intervening posts.
There are also a few who read only posts by "certain people" with whom they enjoy arguing debating. These people may scan the list of posters for familiar names, click on the victim's favored person's name to go directly to that post, and then jump to the end to post their re-BUTT-al. In many cases it's quite obvious that the poster read neither the first nor the last post, much less anything in between.
While there are a number who simply jump to the last post and add their bits of wisdom, it seems pretty obvious that they click into the thread because of the title, read nothing of the previous posts and contributed their little "booger of brightness." A small percentage of these may actually look at the last post, but will not likely be dissuaded from posting.
The most likely cause for a "pause" in a thread, which sometimes is terminal is that a thoughtful poster, having read and considered all the prior content, posts a logical, rational, considered, and thoughtful comment that "breaks the mood" for the most prolific posters, who mostly just interject "smart remarks." Occasonally PoppaGator has been known to be in this group; but I've seen few of his posts that "Killed" a thread, although several may have "bludgeoned the mood."
While the above comments may appear to personally attack a few well-known personalities here, I beg the indulgence of the clones on the grounds that personages displaying virtually all the cited characteristics generally find it impossible to read a post more of than two sentences, and hence will never see, and would not recognize my concise and pithy assessments of their proclivities.
Let the seeking for knowledge and true wisdom continue.