It is stated that the World has an effective range of 10 meters. It is a close range stand, and we know that if any of the Joestar group entered this range of 10 meters, they would automatically be killed by the World with the power of the time stop. It's why Dio doesn't kill the group immediately when they reach his coffin, and it's also why Dio has to chase them. Even with The World's time stop ability, the group was not in range. However, Kakyoin was near the edge of a 20 meter Emerald Splash, yet he was killed. How did this happen?