As the fireball travelled upward, Violette rapidly encased the party in a dome of ice, using the stone walls as pillars. She could hear the harpoons tinking against the surface, before a shockwave shook them.
The ice dome started glowing red for a few seconds, even melting a bit, as the heat around them rose rapidly. Then everything went back to normal.
What told them their plan had worked were the many notifications of killing the monsters that rang in their ears.
Violette melted the ice dome, and what greeted them was not a sight for the fainthearted. Lifeless frogmen, floating about the place, dimly lit by Silent's still ongoing light spell.
The sight was troubling to most of the party, so they started moving forward again, leaving this graveyard behind. Astaroth was thinking of how the scene looked like the interior of sunken submarines in movies.