Thalia had been standing on a frozen creek the entire time without knowing, and because of the situation, even Zane hadn't registered it or noticed until the frozen creek gave way beneath his feet and swallowed him into the freezing water, but not before he pushed the princess away before he disappeared into the water.
When Thalia regained her footing, she stumbled to the edge of the cracked water and cried out his name. The power she used in calling out his name seemed to momentarily demand her vocal cords. Panic and helplessness gripped her chest like a vine, and before she could do anything, he resurfaced from the frozen water, shaking and struggling to climb up from the hole.