While Ralph rested, Clark was able to bring a few of the fire related materials. He even managed to find some small lava rocks that could be heated again by the fire crystals. They would be the ideal materials to force a change in Ralph's taming space. It had to be done to make it perfect for the molten boar.
The molten boar would be forced against the cold metal of his taming pace if Ralph was not careful. The reason this would be bad was because it would push his newly evolved partner in to a dormant state where it could not consolidate its power. It would also stunt its growth for a time since it needed the warmth of fire and strength of metal now that it had become a dual elemental type beast.