Outlaw is exactly right. However, doing this still requires the best use of time to avoid screwing it all up. Since there are four pairs, and one bomb has to be placed 'tween each, going in a u-shaped pattern is about the only way to do this correctly. Gotta practice it for awhile, s'pose.
--- Take me down from the ridge where the summer ends And watch the city spread out just like a jet's flame