Complex sentence: Phase One consisted of meticulously planning, mapping and practicing their locations around the D.C. area so that after each shooting they could quickly leave the area on a predetermined path and move to the next location.
Split into simpler sentences: Phase One consisted of meticulously planning, mapping, and practicing their locations around the D.C. area. This way after each shooting they would be able to quickly leave the area on a predetermined path, and move on to the next location.