BTW the Langweiche article in The Atlantic suggests that the passengers and crew were asphyxiated by flying over 40K feet for a period, hence no objections. Also the the end of the plane was seemingly more violent than simple descent.

This doesn't contradict my vague scenario, but I wrote it after having read the posted article (about the clever ham radio hack) but before reading Langweiche's article which was mentioned in another comment.