The way Katniss moves encourages Ellana. She's light and fast on her feet and so the mage isn't too worried about hitting her by accident. If they go out in the field, she can see them working well together.

Since she wants to avoid destroying the makeshift targets, she'll refrain from fire, but she only knows one cold spell, which she uses now. With a flash of white around her body, she Frost Steps through the next target, whirls around, and fires a simple spell at it.