In his last killing, God killed the 100,000 Syrians for calling him a hill god. But some of the name-calling Syrians escaped. God took care of them by having a wall fall on them, killing 27,000.
But the rest fled to Aphek, into the city; and there a wall fell upon twenty and seven thousand of the men that were left. 1 Kings 20:30a
It was a really big wall.
Note: Benhadad (the king of Syria) somehow managed to escape the falling wall.
And Benhadad fled, and came into the city, into an inner chamber. 20:30b
He asked Ahab to let him live, offering to restore the cities that Syria had previously taken from Israel.
Thy servant Benhadad saith, I pray thee, let me live ... And Ben-hadad said unto him, The cities, which my father took from thy father, I will restore; and thou shalt make streets for thee in Damascus, as my father made in Samaria. 20:32-34a
So Ahab made a treaty with Benhadad and let him live.
Then said Ahab, I will send thee away with this covenant. So he made a covenant with him, and sent him away. 20:34b
God would later kill him and his family for this act of mercy.