Helaman 1:32

And thus had Coriantumr plunged the Lamanites into the midst of the Nephites, insomuch that they were in the power of the Nephites, and he himself was slain, and the Lamanites did yield themselves into the hands of the Nephites.

Coriantumr had led the Lamanites right into the middle of the Nephites. They were in the Nephites’ power. He himself was killed. The Lamanites gave themselves up to the Nephites.

Coriantumr had led the Lamanites into the middle of Nephite territory, and now they were completely at the Nephites’ mercy. Coriantumr was dead, and the Lamanites surrendered.