Sigma's attention is on floating the first unconscious girl towards him, laying her down nearby - close enough to protect from further damage, but far enough to allow a reaction should she awaken suddenly (though there seems to be low probability of that occurring). He keeps an eye on the battle as he releases his grip on the unconscious girl, and there is opportunity-

He calculates the angles and fires his hyperspheres, sending them to ricochet off the ground and implode against the girl's back. It should leave Alice an opening, though with the way she is acting, she may require a reminder. "Do not kill her!"