The world will continue with its business. That's what the world was doing "in the days of Noah." That's what the world was doing "in the days of Lot." The world was going to work, partying, marrying, eating and drinking, starting businesses, planting gardens, and so on. Life continued as it had always happened. The righteous Noah warned his generation, but no one believed him. Lot attempted to warn his sons-in-law, but no one believed him. And in a moment, as the world continued without expecting, the floods began in Noah's day, and fire started falling from the sky in Lot's day. When the rain and the fire came in those two judgments, it was already too late for those who thought life would continue as usual.
Luke 17:26–33 (NKJV) 26 And as it was in the days of Noah, so it will be also in the days of the Son of Man: 27 They ate, they drank, they married wives, they were given in marriage, until the day that Noah entered the ark, and the flood came and destroyed them all. 28 Likewise as it was also in the days of Lot: They ate, they drank, they bought, they sold, they planted, they built; 29 but on the day that Lot went out of Sodom it rained fire and brimstone from heaven and destroyed them all. 30 Even so will it be in the day when the Son of Man is revealed. 31 “In that day, he who is on the housetop, and his goods are in the house, let him not come down to take them away. And likewise the one who is in the field, let him not turn back. 32 Remember Lot’s wife. 33 Whoever seeks to save his life will lose it, and whoever loses his life will preserve it.