That lame camel left behind by the Bedouin. I know the idea is gross, and the one who shot the camel was frustrated and acting in anger, but that camel must have had GALLONS of blood in it. Drain its blood (drag it halfway up a dune to get a gravity assist and a bucket under it), set up a still, capture the water as it evaporates - they could have lasted longer or increased their water ration as they worked.
Not only the water, but the meat. I don't think I'd want to eat camel meat, but if all I've been eating for a while is canned peaches, I bet camel would be pretty appealing.
Yeah, just a bite of protein would have done those guys a world of good.