Prolonged hunger may result in the discomfort of death due to lack of oxygen. But thirst is a long drawn affair. Lord Jesus Christ died on the cross due to suffocation. But his only desire during the last moments of his life was water to drink. If thirst can be so taxing even God incarnate desires of, one can imagine how an ordinary human could drive a thirsty man to go raving mad in thirst. Pi had never before experienced physical hell than that putrid taste and pasty feeling in the mouth. It was an unbearable pressure at the back of his throat. He had a sensation that his blood was turning into a thick syrup that barely flowed through his veins.
