The title "Split the Law" is an anagram for "the past will". The next episode, "Cede Your Soul", rearranges to "cloud our eyes", forming the complete line "The past will cloud our eyes".
"Dirty bombs" come in two styles. Old school was a nuclear bomb designed to maximize radioactive fallout, thereby poisoning large areas of land for decades to come. New school is a chemical explosive, like TNT, that vaporises snd disperses some low grade radioactive material over a relatively small area. The core from a junked X-ray machine and two sticks of dynamite could trigger a mass evacuation in Manhattan.