which apocalyptic senario do you fear the worst?

[Hoofhurr]

Piss will keep you alive a bit longer.

Yeah, but dehydration accelerates water reabsorbtion from your urine. You'd have to start drinking your piss as soon as you run out of water or you'll be drinking concentrated urea. Not sure how much time that buys you.

Agreed. I watch a lot of survival shows and have read a few RL accounts of ship wrecks etc. If you can drink your piss it'll save you for a little while longer in the absence of any alternative. I'm thinking maybe one bladder full before the concentration of urea in your piss does more harm than good.