Nothing is certain in war.

The night-vision goggles cast the road in a soft green glow, a familiar view of Iraq. To 26 Recon Marines, it’s just an ordinary dirt road, marked by a few potholes, weaving its way to a village. Inside the armored vehicles, we sit cramped and drenched in sweat, wishing for even the slightest breeze.

We are a special operations unit, sent on a reconnaissance mission into unfriendly territory. I can’t help but think back to the year before. Will we see as much combat? During our briefings, we were told that the insurgency had subsided. But nothing is certain in war.

With every rock and pothole the Humvee hits, I bang against the metal armor surrounding me. The 100 pounds of gear and ammunition that I carry weigh more heavily as the hours pass. The M249 squad automatic weapon between my legs adds to my claustrophobia.

I scan ahead and to our flank, my vision limited by a dirty, bulletproof window. I can’t see much, but we have escaped death before because one person spotted something out of place.

Around 2:00 a.m., we dismount at a house on the outskirts of a village. We sleep in shifts until dawn and then begin a day of patrols and “knock-and-talks” to gain a feel for the locals. They’re polite, but hardly forthcoming. By nightfall, we pack up to leave with no new intel on insurgent activity in the area.

As my eyes again adjust to the night-vision goggles, Iraq turns an eerie green. Leaving the village, we round a small bend that wasn’t entirely visible from our vantage point the night before.

First there’s a blinding flash, then a deafening sound. My heart jumps to my throat, and in that split-second I know: A roadside bomb. A pressure-plated IED that, somehow, four vehicles passed without detonating. Vehicle Five, about 15 feet behind us, is hit hard, its entire front end gone.

Gunny, our platoon sergeant, lies in a crater the size of a Volkswagen, his legs blown apart. Flesh and blood are scattered across the road and paint the inside of the wrecked vehicle.

Dazed Marines stumble through the smoke and dust, unsure if they’re hit. Doc, our corpsman, is tying tourniquets to Gunny’s mangled legs as the ground around them turns darker.

I run my team’s trauma pack to Doc and hear Gunny, his face twisted in unimaginable pain, ask Doc to kill him.

There should be shock and emotion. I am staring at a man near death, the corpsman who tends him kneels on a gruesome composite of turned earth and flesh. No mind should take in such horror. But in war, cruelty is commonplace. There is calmness in our movements. We have to focus on staying alive. I join my fellow Marines on security, as a radioman requests an immediate casualty evacuation.

The chopper arrives. We load Gunny into the chopper, and the bird takes off.

I dig in on the side of the road. Through a sleepless night, I again watch Iraq basked in a surreal green. Marines about me quietly shift their weapons and whisper into radios. There is no movement in the desert.

At daybreak it starts up again. First come the mortar rounds and 50 cal. sniper fire, then the cracking of AK-47s. I again wonder if I will live to see the next day.

But I did, and so did Gunny. Gunny was there to meet us when the team’s deployment was up five months later, already mobile on his new prosthetics.

That was five years ago. Now I’m a senior at Stanford, studying political science. There aren’t many veterans here, but there are a few of us. They all have memories like mine – of Humvees and craters and worse things. When we talk about Iraq and Afghanistan in class, we have a different perspective from most students.

As the wars draw down, more and more young people return home with memories like these. We study, work, hang out with friends and talk about politics like everyone else. But we always remember one thing, which sets us apart: nothing is certain in war. Not even an ordinary dirt road.

Sergeant Chris Clark ’12 served two tours in Iraq ending in 2007 as a member of the Marine Corps Reconnaissance Unit.