The contact owns a 2013 Lincoln MKX. The contact stated while driving 70 MPH with the radio playing, the contact stated that only the rear speaker was playing. The contact increased the volume to hear the sound in the front speakers; however, while merging onto the highway, the speakers in the front of the vehicle started working and the volume increased. The increased volume of the speakers startled the contact who jumped and jerked the steering wheel. The contact stated that the passenger in the vehicle suffered a panic attack and passed out with his eyes rolling back in his head. No warning lights were illuminated. The vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 145,000.