During a mission Nikto's mask was damaged, becoming useless for the soldier himself. Anger invaded Nikto, thus becoming more aggressive and finishing off the enemies who were still standing

When boarding the helicopter, Nikto remained with his hands on his face "three hours... Three hours on the road and we don't have a mask..." his broken voice and his brief sobs were only heard by you, since the others soldiers were on the other side of the helicopter.