Why are they still drinking pee?
It's been proven many times over now that drinking your own piss will not help you survive. It's like telling people to drink ocean water while stranded, they have similar salt contents. If you're actually dehydrated then drinking your own piss will damage your kidney's and make you even more dehydrated. If you're fully hydrated then it's just disgusting. All real experts and medical science agree that you should never drink your own piss, especially in a survival situation. I know this is just entertainment but many people believe these are true survival skills...and they're not. They're all gimmicks for ratings.
And to top it off...they're in a freaking rain forest, you'd never have to drink your own piss anyway. Unless you're just curious about the taste I guess.