The plan is put into effect. In addition to the flocks and herds, verse 12 indicates that they also took their “gold, and silver, and their precious things.” They believed that they would be able to stay ahead of their pursuers, even with animals to herd and wealth to carry. This was not a desperate flight, but a controlled exodus.
It is certainly plausible that they counted upon Jehovah’s protection in this journey. They may also have decided that the Lamanites might not mount a serious pursuit. They may have also understood that they no longer had options, and that the result of the pursuit might either be their success or their near total demise. They had no more options and took the best possible one.