About Bear Grylls: Mission Survive Season 1, Episode 4 :

The six remaining celebrities go deeper into the unknown and one of them is suffering from mosquito bites while another has trench foot. Bear is looking for the celebrities to be cheerful in the face of adversity, an essential characteristic for a 'Survivor'. They are taken by a military truck to a nearby two-mile cave system. They are shown how to burn the hairs off the taranatulas’ legs to make them safe to eat and they have to use their rope skills to safely navigate the tight spaces and waterfall descents inside the cave system.