John Calvin Commentary Genesis 14:10

"Now the vale of Siddim was full of slime pits; and the kings of Sodom and Gomorrah fled, and they fell there, and they that remained fled to the mountain." — Genesis 14:10 (ASV)

And the kings of Sodom and Gomorrah fled. Some explain that they had fallen into pits. But this is not probable, since they were by no means ignorant of the neighboring places; such an event would rather have happened to foreign enemies.

Others say that they went down into them for the sake of preserving their lives.

I, however, understand them to have exchanged one kind of death for another, as is common in moments of desperation. It is as if Moses had said that the swords of the enemy were so formidable to them that, without hesitation, they threw themselves headlong into the pits.

For he immediately afterwards adds that those who escaped fled to the mountains. From this, we infer that those who had rushed into the pits had perished. Let us simply understand that they fell, not so much deceived by ignorance of the place, as disheartened by fear.