Since there was only Trevis in their group who didn't have a flame, and Adrian who couldn't summon an Elemental with Alaric, they were all really delighted to learn that they would be able to summon Elementals during a fight.
So Mia left the summoning spell out for everyone to check it out, because since they couldn't copy it here, they all had to learn by heart the symbols they had to draw before they could summon an Elemental.
And since there was nothing more to do than to train until the 28th level, where the next dungeon was, they all tried to summon an Elemental.