The most frequent ending in the card game I mentioned is that as soon as it becomes apparent that one player will lose, they take everyone else with them.

(sure, it may be just a game, but I claim there is at least one nuclear power that (a) cannot credibly claim a "no first use" policy, and (b) has been known to have leaders who fail to accept defeat graciously)

It is of course the duty of psychological warfare operatives to provide a non-button path for losing entities (does "cooling the mark out"* assume there are no psyop-immune "Doomsday Machines" in the launch path?); how confident are we they can do so effectively?

* https://www.tandfonline.com/doi/pdf/10.1080/00332747.1952.11...