Ether 14:27

and so terrible was the destruction among the armies of Shiz, that the people began to be frightened, and began to flee before the armies of Coriantumr; and they fled to the land of Corihor, and swept off the inhabitants before them, all they that would not join them;

So much of Shiz’s army was destroyed that the people became scared. They began to run away from Shiz’s armies to join Coriantumr. They ran to the land of Corihor. They forced out all the people who lived there, except for those who joined them.

The destruction among Shiz’s armies was so horrific that his people panicked and began fleeing to Coriantumr’s side. They fled to the land of Corihor, driving out or killing everyone who wouldn’t join them.