With a break in the fighting a distance is created between the two opposing forces. Note that we immediately have Moroni and Zerahemnah in a formal discourse. Neither Moroni nor Zerahemnah would likely have been on the very front line, but the formal discourse between armies is properly carried out between the leaders of each army.
Textual: We have an inserted declaration by Moroni. Mormon has been telling the story, but when it comes to the formal words of the occasion, he copies them in from his source. Moroni will give a fairly protracted request for surrender.