The sudden advantage that had been gained caused many of the soldiers to push themselves in the fights. The change was also where the mages who had been trying their best to attack were able to shine. Specifically the earth mages.
Many elemental mages carried around some of their elemental items with them. Water mages carried more water in drinking containings. Fire mages carried charcoal. Earth mages would often carry stones or earth that they kept close to their body to use as a weapon later. The other mages often had something that allowed them to use the mana around them faster.
Due to this, the earth mages finally were able to pull the stones and earth from nearby their bodies and begin to use it. They knew that once they used the earth to trap undead, that they were at a loss. They would not have it to fight any longer.