"had compassion on Lot." Yahweh is described as being "merciful" because he was sparing the lives of Lot and his family instead of destroying them when he destroyed the people of Sodom for the wrong they had done.
The phrase "at the city" is understood. AT: "Do not look back at the city" or "Do not look back at Sodom" (See: [[rc://en/ta/man/translate/figs-ellipsis]])
# on the plain
This means the plain of the Jordan River. This refers to the general region of the Jordan River.
# so you are not swept away
It is understood that they would swept away with the people of the city. This can be stated in active form. AT: "or else God will destroy you along with the people of the city" (See: [[rc://en/ta/man/translate/figs-ellipsis]] and [[rc://en/ta/man/translate/figs-activepassive]])
# not swept away
God destroying the people of the city is spoken of as if a person were sweeping away dust. (See: [[rc://en/ta/man/translate/figs-metaphor]])