Bruce didn't know exactly how he would accomplish this goal, but in time, he found a way. He began educating himself. Being the heir to a multi-million or billion dollar estate gave him access to the best education money can buy. At the same time, Bruce physically trained himself in many forms of martial arts. While his intent was to have a career in law enforcement, he soon learned that sometimes Law and Justice are not synonymous.
Criminals can too easily slip through the cracks of the legal system and walk free.
He decided that vigilante justice was the only way to fulfill his promise of vengence. It's almost impossible to show every psychological nuance that makes up the Dark Knight in a single two-hour movie. I was hoping that the latest series of movies would build the character more and more with each sequel. The movies are accomplishing this, but not at a fast enough pace. Mask of the Phantasm , did more character development than the combined efforts of the first three movies.