Seeing her allies get covered in the swarm makes Mika hesitate slightly before she releases her magic. "Oh, God. If I electrocute them then I will hit you!" But with Jon's command she views it best to do it any way. So she releases a torrent of electricity towards the swarms

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5ft step forward.
burning hands directly forward hoping that they grubs will get off of Jon's and Huril's bodies.
Reflex DC 16 causes half damage
damage (3d4+1)[8] electric damage