As the group went to further explore the palace, especially the area where they potentially kept their treasures, the battle between Mares and the elder was reaching a climax.
Even with his variety of techniques, the gap of experience between the two could not just be tapped with just using a bunch of different powers at once.
His lightning did damage to the elder, but he lacked enough fine control over it to properly use it in battle. That was the overall problem with some of his techniques actually.
One of the techniques that Mares did manage to make most use of was his berserk energy.
It was the first time the elder came in contact with it, but he saw with a glance that it was something very tricky to deal with.
If he was on the peak of the Third Tier instead, the elder knew that the berserk energy would have probably been enough to spell his defeat.