After completing several practice instrument approaches at night, the flight crew decided to finish the flight with a simulated single-engine approach and landing. The simulated right engine failure was accomplished using the manufacturer's recommended procedures. The flight crew was cleared for the instrument landing system (ILS) runway 30L approach, circle-to-land on runway 12R. The dual-student flew the instrument approach to the minimum descent altitude and then circled to the south to join the right downwind for runway 12R. The dual-student climbed to traffic pattern altitude while on downwind and extended the landing gear when abeam the touchdown point. When the airplane turned onto final approach, it was slightly above the glide slope, at 90 knots, and left of the extended runway centerline. When the airplane was on 1/4 mile final for the runway, it was on glide slope and fully configured for landing. At this time, the airplane was still left of the extended centerline, approximately aligned with the runway edge lighting. About 20-30 feet above ground level, the dual-student banked the airplane about 10-15 degrees to the right. The flight instructor stated that the student's actions made him uncomfortable, given the proximity to the ground. He assumed control of the airplane and initiated a go-around. The airplane yawed and banked to the left as he advanced the engine throttles and pitched up for the go-around. His corrective flight control inputs were ineffective, and the airplane impacted left-wing low in the grass area off the left side of the runway. No flight control anomalies were noted during a post-accident inspection.