Plot hole: They all drop their backpacks and bags 3/4 mile down into the hole before climbing by rope into the caverns to begin their journey. Later in the movie, they are all sitting deep in the caverns complaining about the lack of water supply. Suddenly the long-haired guy pulls out a large glass bottle of gin, completely intact and they all drink from it. There is no way his pack could have fallen 3/4 mile onto a hard surface without that bottle breaking.