Because they will be changed, in a moment, out of the present [physical] life into a spiritual nature. However, those who belong to that last generation will by no means precede the dead.
Israel as a people will have rejected Jesus as their Messiah until that time; but then they come to know that the Christian congregation was indeed pleasing to God, precisely because its members lived by faith towards Messiah Yeshua (Jesus), and on that basis walked in righteousness with God .
We assume that nothing in the world escapes YHWH Elohim's attention. And certainly not catastrophes of such magnitude, and of such far-reaching proportions. After all, God's eyes are constantly circling the whole earth (2Ch 16:9).In addition, we also know with certainty that his (as well as our) great Adversary, Satan, is always out to destroy everything that is in the eternal interest of mankind. Hence it would not surprise us at all if the current world catastrophe will be used by Satan to also nullify the effect of the Rapture of the Christian Church if possible.