Survival is key in Chult. The heat, the rain, and the diseases are just as deadly as the monsters. The Tomb of Annihilation PDF contains the rules for dehydration and exhaustion. DMs reference these constantly. The digital format makes it easy to check the saving throw DCs for diseases like Mad Monkey Fever. It ensures the survival elements are applied consistently. The PDF transforms the environment into a constant threat, forcing players to plan their expeditions carefully and manage their supplies.