I think that this was a mistake in this case to ditch the beer straight away. If your going to find a backpack just lying their in the middle of Zambia with cans of beer, then there is always chance of finding the other backpack companion holding the lemonade. There is nothing like a Shandy to quench the thirst later on when you eventually find a water source to cool off the beer.

2 cans of beer would also be equivalent to 300-400 Kcal of energy being thrown away, if water to quench dehydration wasn't a problem.

But then again the empty beer can makes for a fine container for Joe Teti's urine, which in other episodes he doesn't have much of a problem drinking. Must be a Special Forces thing.