(Jehovah's Witnesses view) Jesus statement about Great Tribulation and the situation due to which "no flesh will be saved" This question is about Jehovah's Witnesses understanding of Jesus words in Matthew 24:21-22:


  for then there will be great tribulation such as has not occurred
  since the world’s beginning until now, no, nor will occur again. In
  fact, unless those days were cut short, no flesh would be saved; but
  on account of the chosen ones those days will be cut short.


My question is particularly about the part "unless those days were cut short, no flesh would be saved".

It looks to me like Jesus was saying that the situation would be such that no flesh or life would survive, unless those days are cut short. Like as if he is referring to some severe threat to all life on earth. Unless I am misunderstanding the word "saved".

I checked the articles I found about the Great Tribulation at jw.org (such as this article titled "What Is the Great Tribulation?" and this article) but did not find an explanation as to why "no flesh would be saved".

Questions:


Do Jehovah's Witnesses have an opinion on whether this passage
refers to a situation in which all life on earth is threatened? (Or
does the word "saved" here refer to no humans somehow being "worthy"
to be saved?)
If if refers to a situation in which the survival of all life is
threatened, what is the cause of this threat? For example is it
because of some action by mankind such as World War 3 or something
like that?
Jehovah's Witnesses believe the prophecy at Matthew 24:15-22 has a double fulfillment.

The first fulfillment came about when the Roman army surrounded Jerusalem in 66 C.E., but then the attack was cut short when the Roman army suddenly withdrew. The faithful disciples in Jerusalem and Judea recognized this as their chance to escape, while the rest of the city thought it was a victory. The Roman army then returned and destroyed the city in 70 C.E.

In parallel, the second fulfillment will come about in the Great Tribulation. At that time, there will be an initial attack on religion by the "disgusting thing ... standing in a holy place," which is the United Nations. The attack will be cut short to spare the true religion from being destroyed also.

Here's an infographic from the 2013 Watchtower article, "Tell Us, When Will These Things Be?"



In summary:


The attack is against religions and their adherents.
The attack is caused by the world's governments by means of the United Nations.


For a much more detailed analysis of the events leading up to Armageddon, see the book God's Kingdom Rules, chapter 21: "God's Kingdom Removes Its Enemies."



P.S. I'm impressed by how in-depth this question is. There are a lot more research tools that can help you find answers quicker in the future. One of the most useful ones is the Publications Index, where you can find publications by Scripture or by topic. (It's what I used to find information for this answer.) You can also use the search feature on https://wol.jw.org for a broader range of articles than are available on just the main site.