Matthew 24:38-42 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.
They(the ones eating and drinking, etc.) and them(the ones taken away) are the same in this passage. Noah and his family were left and remained safe in the ark(a typification of being in Christ). The man in the field and woman at the mill taken away are taken to destruction, not salvation. This is not the same happening spoken of in Thessalonians(called the rapture of the Church). Those people taken unto Christ in the clouds are the saved in Christ. Two different takings.
Luke 17 speaks likewise only doesn't use the wording "took them all away" as with the ultimate clarification in the cross reference of Matthew.