Well, it would seem Kira had underestimated the captain. She figured she was a good hand to hand fighter, but Majick........that, she was not expecting. It just further proved that Kira wouldn't be able to stand against her in a fight. Hand to hand, while Vieras were naturally athleting, Nell was much more skilled. And while Vieras had a natural affinity for magic, and Kira might be somewhat equal to her, the experience Nell possessed would likely lead to a win.
Still, she stayed hidden to watch the action from a safe spot, wanting to see that goddess in action, but it was short action. Seeing the spell and lightning, the men quickly fled.