 Once they reached chamber three, it was time for the second phase. Each boy was secured on a stretcher and carried to a team of at least five men. At one point, they had to place a stretcher on a raft and pull it across a chin-high pool of water. Rescuers had to winch the boys up on a steel slope using a pulley system, and in some rocky areas, they formed a human chain, passing the boys hand-to-hand while others slid them on top of pipes pumping out water.