The armies clash without a decisive victor. At the end of the day, they retire. This is quite typical of battles in the ancient world. Fighting at night was unusual, and at the end of the day any unresolved battle would frequently simply disengage. (Ross Hassig. Aztec Warfare. University of Oklahoma Press, Norman. 1988, pp. 104-5).
The howlings and lamentations of verse 16 are a very authentic addition to the text. Not only would such sounds accompany the loss of life, but they would be a dramatic part of Ether’s experience from his distant location. He might not see much or the specifics of the battle, but he would certainly hear the clashes, and in the still of the night the sounds of mourning would be particularly audible and poignant. We may expect that this particular detail is original to Ether’s record.