Lot's arc is almost done. Genesis 19:30 places him, finally, where the angel originally told him to go in Genesis 19:17 — the mountain.
"And Lot went up from Zoar, and dwelt in the mountain, and his two daughters with him; because he feared to reside in Zoar. And he dwelt in a cavern, he and his two daughters."
The Targum's Aramaic word for "cavern" — m'artha — is the same word that will later describe the Cave of Machpelah where Abraham and Sarah will be buried. But the parallel is bitter. Abraham's cave is a monument to a completed covenant and a treasured wife. Lot's cave is a hideout for a broken man with no wife, no sons-in-law, no home, no community — only two surviving daughters.
Why is Lot afraid to stay in Zoar? The rabbis of Bereshit Rabbah read the fear as theological. Zoar had been spared only temporarily, and Lot suspected that its reprieve might not last. If Heaven had destroyed four cities in one morning, what was to stop it from striking the fifth tomorrow? Better to climb the mountain and sleep in a cave than to sleep in a city that might still be on God's list.
There is also a psychological reading. Lot has just watched his entire world dissolve into fire and salt. He cannot imagine ever trusting a city again. So he flees even the small refuge he fought for, and hides in stone.
It is from this cave, in the verses that follow, that Moab and Ammon will be conceived — two peoples who will haunt Israel for centuries, and from whom, eventually, Ruth the Moabitess and King David will descend.
The takeaway: even the smallest rescue sometimes ends in a cave, and even a cave can be the birthplace of a king.