Well, it certainly makes the argument less persuasive because it doesn't fit with all the other parts. I think my original version is better.

In seriousness - actually comets are a lot like car accidents (if you believe that comets aren't actively trying to kill you), the only difference is the probability distribution (and you used the comet example because of the higher variance.)

Unlike those things, the success of an intelligent being trying to kill you cannot and should not be thought of as a probability distribution. It's not like a coin being tossed, in that a coin doesn't tend to get better at falling on one side or the other (nor do car accidents or comets get better at killing you, so they are more like coin tosses.)

It matters whether there's intelligence behind the cause or not; I'm surprised at how hard this point is to make at a forum occupied mostly by programmers.