It's pretty amazing when you think about it. Even given Musk's erratic behavior in the previous weeks, it would have been hard to predict something like this.
At a short notice summon the handful of engineers who survived the purges to the office at 2pm on a Friday and to bring 10 screenshots of code they've written "for review". With that implicit threat, have them wait until 6pm. Then keep them around until 1am to give a tutorial level introduction to the Twitter infrastructure to Musk (who could have gotten this months ago). There's just no legit justification for it; it's pure bullying and a loyalty test.
And then to top it off, have your pet venture capitalists post fawning tweets about how this really shows the classic SV energy.