Were any means of communications available to 150 people over 8 minutes I suggest someone would have got a message through. Yet they did not.
That assumes they were aware of something seriously amiss that would warrant sending such a message. Although the descent was steeper than usual, (about 500-600 ft/nm?) it doesn't appear to have exactly been a screaming dive - and the onset appeared to be quite smooth.
(Caveat the above with the fact that I'm using the FR24 data which may contain inaccuracies)
Having had cause to don an oxy mask in anger in the distant past, I found that it could be done well within the oft-quoted TUC figures, even when taken by surprise.