Matthew 24:16-20...Then let them which be in Judaea flee into the mountains: Let him which is on the housetop not come down to take any thing out of his house: Neither let him which is in the field return back to take his clothes. And woe unto them that are with child, and to them that give suck in those days! But pray ye that your flight be not in the winter, neither on the sabbath day
About the one left standing - not to mixed up with the Rapture?
Matthew 24: 36-41...But of that day and hour knoweth no man, no, not the angels of heaven, but my Father only. But as the days of Noe were, so shall also the coming of the Son of man be. For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until the day that Noe entered into the ark, And knew not until the flood came, and took them all away; so shall also the coming of the Son of man be. Then shall two be in the field; the one shall be taken, and the other left. Two women shall be grinding at the mill; the one shall be taken, and the other left.
Those who are taken by God - will be condemned into Eternal Judgment. The accepters of Christ (people left standing) will remain; the rejecters of Christ will be cast into outer darkness.
Matthew 25:30...And cast ye the unprofitable servant into outer darkness: there shall be weeping and gnashing of teeth.
Revelation 20:5...But the rest of the dead lived not again until the thousand years were finished.
2 Thessalonians 1:6...when the Lord Jesus shall be revealed from heaven with his mighty angels, In flaming fire taking vengeance on them that know not God, and that obey not the gospel of our Lord Jesus Christ:
In the days of Noah - Noah preached for 120 years. Only 8 souls got into the ark. Noah preached and people were nonchalant about the coming of the flood. A fierceness and wrath of an Almighty God took the rest of humanity away in the waters of the flood. So shall the coming of the Son of man be another Divine Judgment. That very Judgment will take place when the Son of Man steps down on the Mount of Olives - after His fire has purged the Earth - unlike the days of Noah when God's Judgment came by water.
"In the Rapture - Christ calls the Church up to escape Judgment on Earth. In the coming of the Son of man the Church returns with Christ; and Christ with all His saints - step down on the mount of Olives - bring Judgment to Earth".