Front Seat Belt Buckle Assembly problems of the 2001 Subaru Forester

Wife was driving our 2001 Subaru Forester. She got too close to edge of paved surface on narrow secondary road and tires dropped off edge. Instead of there being the required flat shoulder or berm, there is a 4+ inch drop at that point. The drop and correcting to the roadway caused her to lose control and the vehicle ended up rolling two or three (witness accounts varied) times and ending upright in a field. During the very first rollover my wife was aware of the seat belt coming unlatched. Obviously, she then became an object being tossed about in the vehicle during the rest of the crash sequence. There is no evident, physical damage to the belt or buckle mechanism. The inertia lock still functions; the belt will click into the buckle and remain there with a tugging motion is applied. Obviously I can not duplicate the type of forces that were applied during the crash. I contacted subara of America at their customer service dept with this information and they would only look into this in the event the insurance company seeks to subrogate the claim to them. This will not happen as the seatbelt did not cause the accident (for collision loss part of claim) and pennsylvania law does not allow subrogation for medical claims. I was not seeking a litigation settlement in contacting Subaru. . . I thought it would be something they would want to investigate before someone was killed.