The Magelets are easily herded. They want to play in the slush some more.

Mistral will nod to Rydia, and hang back for just a moment longer... once he's certain the Magelets are out of range and won't have any awkward questions, there will be some heavy use of ice magic. Then, with Black Waltz One buried as well as could be managed under the circumstances, he'll rejoin the others and they can leave the Ice Cavern behind.