What do Salva and his group face when they reach the other people in the desert in A Long Walk to Water?

Salva and his companions encounter a group of six soldiers as they walk through the desert in chapter 10. The other men are armed with rifles and machetes and are part of the Nuer tribe. They order the others to sit on the ground with their hands on their heads. One of the soldiers identifies Uncle Jewiir as the leader of the refugees and they tie him to a tree. After robbing the group of anything of any value that they had, they murder Uncle Jewiir.
With the loss of Jewiir, cohesiveness in the group begins to crumble. They no longer share their food with Salva and seem to take an "everyone for themselves" approach to survival. This only serves to encourage Salva even more to survive, and they soon make it to the massive refugee camp on the edge of the desert.