Ever stumble across a dead body?

It happened to me once in the Central Sahara.

I was camped at a mountain called Jebel Uweinat, right on the border of Sudan, Egypt and Libya, some 600km from the Nile and the nearest villages. Just about the last place you’d expect to run across anyone.

I’d gone there with a small multinational group searching for prehistoric rock art. We were struggling up a dry wadi one morning, and my wife was walking ahead. She came running back to tell me they’d found a dead man.

Of course, I didn’t believe her at first. But as I walked deeper into the wadi I saw a ragged pair of trousers, and then a shirt. Beyond it, there was a discarded head torch sitting on the ground. And then a plastic sack which must have contained bread, next to an empty water jug that was far too small for a place like that.

The man — or what remained of him — was lying beneath a rock. There wasn’t much left of his face, but his arms and legs were still covered in flesh.

A member of our team found a piece of paper in the pocket of the trousers, but it didn’t contain any clues to the man’s identity. Just a tightly-packed list of names and European phone numbers written in what looked to be Eritrean. The rest of his story emerged by sheer coincidence when we returned to camp late that night.

One of our group had been there on a separate trip 4 months earlier, when a man staggered out of the desert and into his camp. John told us his visitor was Eritrean, and had reached Uweinat on foot after catching a lift with gold miners, groups of desperately poor men who were scouring the desert for surface finds using shovels and simple tools.

They’d taken the man as far as their camp, and told him to walk in the direction of Jebel Uweinat, where he would be sure to find water. After locating Uweinat, he should walk onwards to the oasis of Kufra in Libya, which he would reach after another day. From there, he could get to Europe.

The miners were either lying or they had no idea where they were. There was no water to be found at Uweinat, and Kufra is 355km away, over flat, featureless, broiling desert. He didn’t have a hope of crossing it on foot. John gave the man shelter for the night and supplied him with food and water. And when morning came, he told him to go back to the gold miner’s camp, and back to Khartoum.

The thing is, this Eritrean man hadn’t set out alone. He’d been walking with a friend. The two of them had separated a day earlier, after disagreeing on which way they should go.

It was the friend whose body we had found.

He must have wandered into the wadi because he saw acacia trees at the entrance. Perhaps he hoped he’d find water there. He crawled beneath the shade of that rock with the last of his strength, knowing he’d never make it out again, and knowing no one would find him.

Can you imagine how it feels to die like that?

The first terrible symptom is thirst. That sensation of thirst never leaves you in the desert, but this is different. As serious dehydration sets in, you begin to urinate less: dark, sluggish urine that eventually turns black. And then you stop sweating, and your body temperature rises. Your head starts pounding as your blood thickens, and your heart rate increases with the struggle to maintain oxygen levels.

As your blood pressure drops, you begin to experience fainting spells. This is when things start shutting down. Your body can’t maintain blood pressure, so it slows your blood flow to non-vital organs like your kidneys and gut.

By now, you’re losing salts, without which your muscles can’t function. You become clumsy, stumbling around, wracked with excruciating muscle and stomach cramps. Feelings of nausea may cause convulsive vomiting, which only makes you lose more fluid. You aren’t thinking rationally anymore, but out there, it wouldn’t matter anyway.

Your tongue swells to fill your entire mouth. As the water that makes up 65 percent of your body dries up, you lose weight very rapidly. Your eyes shrink back into your skull, and your brain shrinks, too. As it does so, the blood vessels connecting your brain to your cranium can tear away and rupture.

Your kidneys eventually fail, causing toxins to accumulate in your bloodstream. At some point, you begin to hallucinate, seeing things that aren’t there, memories mixed up with waking dreams. This stage is often accompanied by seizures, and sometimes the vomiting of blood. You might tear off your clothes because, by now, your skin and nerves are burning, and your clothing feels like sandpaper. Your body’s cooling system is no longer working, and you’re quite literally baking alive.

You’ll eventually slip into the merciful oblivion of a coma before your life fades out. But it can take up to a week.

Did this young Eritrean man think of his family as he lay there dying alone in the sand? Did he pray for help? Or did he just feel regret?

A team member from our expedition took that scrap of paper back to civilization and called the numbers written on it. One belonged to the dead man’s mother. He tried to tell her that he’d found her boy, but she was hysterical. She accused him of being a people smuggler and of killing her son. I hope she never knew how long it took him to die out there.

How bad does your life have to be to take such a risk so you can get to a better place?

There are many more forgotten bodies lying along the trans-Sahara routes, but the migrants shivering in storm-tossed boats and drowning in the seas between Libya and Malta are dying within reach of help.

What would you do if you’d found that man still clinging to his life beneath a rock in the desert? Would you give him water and shelter?

Or would you look him in the eye and tell him you’d like to help, but that you’re sorry, it would just set a precedent and others might expect water and food from you, too?