The hot weather made everyone sweat all the time, and there were so many of them that water consumption was tremendous. It was almost five to six times higher than usual. Although they had collected a few drops before by using leaves, the amount was limited and the process was very time-consuming. Plus, that water was only sufficient for survival, not for daily use.
The high temperature made everyone very uncomfortable when they did not shower for a whole day. If anyone fell sick under those conditions, he or she would have to struggle to survive. It was very risky and unreliable to collect water that way. If there was any strong wind at night, or the leaves were destroyed by mutated beasts, it would be a disaster. Finding a steady source of water had become the biggest problem the team was facing.