The chapter
Simply They go in, the rain comes, the waters rise until the mountains are covered, and everything on dry land dies. The chapter ends with the waters standing on the earth.
Context The chapter is dated with unusual precision, to the year, the month and the day, and then gives two durations that are not the same. Both are in the text and the file reports both.
Verses 1-16
Simply Seven pairs of every clean animal and of birds, and two of the unclean. Seven days later the rain begins, for forty days and forty nights. They go in, and the Lord shuts them in.
Context This is where the count differs from the instruction three verses earlier, at 6:19, which said two of every sort. Both are bound so the reader compares them. The last clause of verse 16 is easy to pass over and is the only action God takes in the chapter after the rain begins.
Verses 17-24
Simply The flood lasts forty days, the vessel is lifted, the high mountains are covered, and everything that breathed on dry land dies. The last verse says the waters were on the earth a hundred and fifty days.
Context TWO DURATIONS, BOTH IN THE TEXT: verse 12 has the rain fall forty days and forty nights, and verse 24 has the waters on the earth a hundred and fifty days, with the next chapter repeating the hundred and fifty at 8:3. They are not the same measurement and the book does not reconcile them. The file reports both and binds all three verses so a reader can see it directly.