Here’s a strange but brutal thought:
The energy blast from a bolide (asteroid) large enough cause an extinction or near extinction event will take hours to circle the globe.
I just finished watching the Netflix movie “These Final Hours” which portrays this exact scenario. With an impact in the North Atlantic the resulting shock/fire wave took 12 hours to travel at 1000 miles an hour around to Perth Australia. People some distance from the impact all had hours in which to contemplate their demise. Some, like those in Perth, had half a day of waiting.
Of course the impact from such a rock would be known, most likely, months in advance. But still, few would be able to prepare well enough, dig deep enough, relocate into deep mines and caverns in large enough numbers… Most would be left to worry for months, and then after the impact, still have hours to agonize over the terrorizing affect of the firewave.
The movie does a good job depicting the stoicism, the freak out, and the Bacchanalia that would ensue. But the deliberate delay of death caused by the wave traveling so far — that — that was the insight I’ve missed from other apocalyptic stories. Like waiting for the hangman on hanging day. It permeated the theme of the movie. Good job.