Terry wasn't interested in a straight up fight. He was more worried about the fact that, in VERY rare circumstances, you could actually shatter solids like they had been made out of ice, rather than whatever they had been. Getting Star out and clear was more important than finishing the boss. Which was why he caught her before she could slam into the ground, and began backing up, firing rounds at the boss with less intent to hit, and more intent to 'encourage a strategic withdrawal.'