The king had a mutant rat problem in his kingdom, so he ordered 3 young men to go down under the depth of the ground to find the cause. The 3 young men jumped down the hole, and followed the tunnel. After hours of walking, they met an intersection. There were 4 paths at this intersection. The king had told them before they left that there would be at least 1 safe path.

One by one the soldiers went down a tunnel. The first one went... The other two heard a scream! Certain death met them there. The second went down the second path. Scream! Then the last knew for certain exactly which path was safe. He soon found the source of the problem, and reported it to the king.

How did the young soldier know which path to take?