Noah and those who fled with him are overtaken and they engage with the Lamanites. It is unlikely that those who went with Noah were the younger men or the warriors. They were more likely to have been the elites, and perhaps not as experienced in combat. In any case, it became clear to Noah that they would be slain, so Noah commands that they leave the women and children and flee.
Certainly, this appears reprehensible. It was sufficiently difficult for some that they could not do it, and remained with the women and children. However, what followed might have been part of the plan in leaving. If we give Noah the benefit of the doubt that Mormon does not want to accord him, it is possible that Noah expected that the pleading of the women might be effective. It is a tactic that we saw at a time when Nephi’s brothers and Ismael’s sons wanted to kill him, and the women intervened. We will see it again with another group of women. It is possible that this was understood as an acceptable means of surrender and cessation of conflict.