Park Choong-kwon was once a member of an elite North Korean unit that developed long-range missiles. Now, as a lawmaker in the South, he is sounding the alarm over Kim Jong Un's weapons. As a teenager in the North, Park was plucked from his regular classroom and sent to a school for gifted kids, from where he quickly progressed to the country's National Defense University. But he disliked the military discipline and was disillusioned by high-level corruption, eventually deciding to defect to the South, where he was sworn in as a lawmaker last month. IMAGES AND SOUNDBITES