An insurgent ambush yields a hero, and a wounded soldier recovers back home. Sixth of a seven-part series on the longest deployment of the Iraq war.It all looked as if a video game had come to life.Through his night vision goggles, Staff Sgt. Chad Malmberg saw the insurgents scurrying from berms to canals. Some popped up, ran a few yards, then fell to the Americans' gunfire. But others kept advancing toward his convoy.Malmberg's rocket counterattack hadn't stopped the enemy. And Truck 4, at the back of the convoy, had just radioed two urgent pleas for help.It was running out of ammunition. And the enemy was within shouting distance.Once again, Malmberg ordered his truck to race to the back -- this time with two other Humvees, one of which supplied .50-caliber machine gun bullets.The insurgents, once five or six football-field lengths away, were now within 50 feet, hunkered in a ditch. When their muzzles flashed, Malmberg saw their faces and their turbans.When his truck stopped, he flung open his door and hopped out, quickly lobbing a grenade into the ditch."Frag out!" he shouted so others could take cover, then repeated the alert on the radio. Then his truck stopped again and Malmberg's driver threw a second grenade.Finally, that threat was eliminated.Still, the fight wasn't over. Insurgents near the front of the convoy, where Malmberg now returned, were launching rocket-propelled grenades as all five Humvees sprayed the area with gunfire.In the midst of this, Malmberg's gunner alerted him that smoke was billowing from both sides of the cab of a civilian truck. Malmberg looked through his rearview mirror. Surely, he thought, the driver was dead. He radioed an order to a Humvee crew: Remove the body.But when the sergeant opened the door, the driver popped out and hugged him. Miraculously, the man had survived, so frightened that he then crawled under his truck for safety.The sergeant pulled him out. They had to go. Now! They had to get out of the kill zone.And they did.When the Humvees returned to base, Malmberg and the others set up a board to reconstruct what had happened in the 55-minute firefight. It was almost impossible. There had been so much chaos. The gunners had shot so many targets. No one knew for sure how many of perhaps 30 to 40 insurgents were killed.They did know this: No one in the convoy -- soldiers or civilian drivers -- was dead. No one was even injured.And Malmberg, whose greatest worry was that he might somehow fail his men, would be decorated as a hero.U.S. troops were not the only targets of the violence that flared across parts of Iraq in early 2007. Ordinary Iraqis, too, found themselves in the middle of a firestorm.Sgt. 1st Class Cassandra Houston was in her second day as a nurse in the intensive care unit at the sprawling Balad Hospital when an Iraqi family was wheeled in for "comfort care" -- the father, mother and son were about to die. All she could do was help them go peacefully.They'd all been shot in the head, apparent victims of sectarian hatred, and the parents succumbed quickly.Their son, around 14, was unconscious but still breathing. Houston suctioned blood from the boy's mouth, changed the gauze bandage on his head and tenderly held his hand.She wanted to make sure he did not die alone.She thought of her son, Josh, who was about the same age.Afternoon gave way to evening as Houston stayed by the boy's side. She watched the monitors as his labored breathing subsided, his blood pressure dropped and his heartbeat dwindled.When the boy died, a chaplain returned, and Houston, along with other nurses, gathered around his bed for a prayer.That night, back in her room, she cried. She called Josh and told him she missed him.And she was back in intensive care the next morning.As she stood by others -- including wounded, frightened troops -- in the months that followed, her eyes might tear up but she learned not to cry every time she saw something terrible.At times, she wondered if she had a heart anymore.At the end of February, a dump truck loaded with gravel and explosives veered into a crowd of worshippers leaving a Sunni mosque in Habbaniyah where the imam had spoken out against extremists.Dr. Joe Burns heard the sirens wailing. Within minutes, dozens of injured Iraqis arrived at the gates of Al Taqaddum Air Base.One was a little boy, around 8. He was unconscious. The top of his head was wrapped in a blood-soaked bandage, a bone jutted through his left leg. His breathing was shallow, his pulse rapid.Burns called for breathing tubes and when he removed the bandage from the boy's matted hair, he saw a hole the size of a quarter in the back of his skull. The gray matter of the brain was visible.He gingerly felt for shrapnel or any foreign material, but found none. That was good news.Suddenly, the boy regained consciousness, sat up, started crying and reached for his head.He told the interpreter his name was Youssef -- Joseph, like the doctor -- but little else before lapsing back into unconsciousness.Burns and others lifted Youssef's stretcher from the floor, weaving through a crowded hallway toward an open bed. As Burns prepared to give Youssef medicine so he could insert a breathing tube down his throat, an emergency room doctor arrived."What have you got?" he asked."Open fracture. Open head wound," Burns replied.The doctor shook his head."No," he said, "make him expectant." Put him aside to die, because others could be saved.Burns protested gently.No, he talked, he regained consciousness, Burns said. He's young, this isn't beyond hope.Eying the boy again, the doctor reconsidered."OK," he said, "do you want me to fix the head wound?"The doctor sutured the scalp as Burns trained a flashlight on it and held a temporary breathing tube in the other hand. He and five other doctors worked shoulder to shoulder, their arms, legs and heads tangled around a nest of tubes, cables and medical equipment. Dozens of other doctors and nurses struggled to save other patients, wading through ankle-high piles of torn-off bandages.Some died, but others survived.And Youssef? Once the boy was stabilized, he was flown to Baghdad for treatment.Later, Burns would try to check on the boy whose life he helped save, using a computer that tracks patients. For six weeks, Youssef's name appeared. Then suddenly one day, it was gone. Burns heard rumors the boy had gone home; he would never know for sure.But on that February day when he fought for Youssef's life, the North Dakota doctor had a final duty.He walked a mile to a base morgue to establish the cause of death for two Iraqi civilians killed in the blast and two U.S. soldiers.He signed the paperwork, then ended his 19-hour day with an e-mail to his wife, Becky. He feared she'd hear news of the bombing and worry. "I am fine," he wrote. "Disregard news reports."As it turned out, she hadn't seen the news at all.At Walter Reed, a new reality was setting in for Sgt. J.R. Salzman, recovering after the loss of his lower right arm.He'd thought he would get a prosthetic arm, rebound quickly and be just fine. But after several surgeries -- including the amputation of his left ring finger -- it was becoming clear: This wasn't a two-week recovery. It would be months, even years.Salzman, who had been the go-to guy when a Humvee needed fixing in Iraq, now had to learn how to do the most rudimentary things: Zip a jacket. Brush his teeth. Write with his left hand.He was haunted by nightmares. Sometimes he dreamed he saw the flash of an IED explosion. Other times, he woke screaming that his arm was gone, begging for a tourniquet.The methadone and Lyrica he took for nerve pain left him dizzy, confused, drowsy. He had trouble remembering appointments.Even proud moments turned into ordeals.When Salzman was invited to the president's State of the Union address, it took 20 minutes and help from his wife, Josie, just to put on his dress uniform. It was his first trip outside Walter Reed; he didn't like leaving his safe haven.As they listened to the speech, which was interrupted several times by applause, J.R. couldn't clap. Josie felt like crying, and applauded loudly on his behalf.Josie was insistent that J.R. talk with a therapist. She didn't want to put it off. Her husband, an athlete, a champion log roller, had lost his right hand. He needed to talk with someone about it.When they finally arranged to meet together with a therapist, it did not go well.Josie thought J.R. wasn't being honest, that he said he was eating and sleeping well, when he was having nightmares and living on pudding snacks.Tensions mounted. He threatened to send her home. He thought she expected him to be the same person with whom she had fallen in love, and he wasn't.But as the months passed, Josie stayed and J.R. improved. He learned to write left-handed, to dress himself, even to fly fish with a prosthetic arm.His sadness, though, lingered. He found himself remembering small details about the hand he lost, down to the scars he had from carpentry work. He'd think about that day when his wedding ring was snipped off by bolt cutters at the Green Zone Hospital in Baghdad.Salzman knew others had worse injuries. He wanted to be positive, but sometimes it was hard."I think having given two years of my life and my right arm is more than enough for my country," he wrote in his blog. "Now I want to get back to my private life, and learn how to live again all over."As spring approached, Sgt. John Kriesel prepared to take his first steps on prosthetic legs.He wanted to walk earlier, but he had to heal from back surgery needed so he could bear weight on his legs. His spine, sacrum and pelvis had to be fused.Kriesel had prepared for months, watching other amputees being fitted with prosthetic legs. His left leg -- which was amputated above the knee -- was replaced with an aluminum limb that bends like a real leg; a computer chip inside senses if he's going to fall and lock ups to prevent it.His artificial right leg -- shorter because his leg was amputated six inches below the knee -- has a carbon-fiber foot with a high-tech shock absorber.On March 12, 2007, Kriesel donned a stars-and-stripes T-shirt and red shorts, wheeled into the therapy room, grabbed the parallel bars and stood.At first, he felt as if he was on stilts.But he was thrilled to look at people at eye level and kiss his wife, Katie, standing up. He walked back and forth, heel to toe, heel to toe, to perfect his form.A doctor had warned Katie that because John's spine was fused, he'd lose mobility in his lower back and would waddle. His gait, though, was smooth.Kriesel worked up a sweat but was reluctant to quit. Only when therapists started switching off the lights at the other side of the room did he stop. They locked up his prosthetic legs so he didn't try to practice when no one else was around.Five days later, Kriesel graduated to a walker.Two weeks later, he had two canes.At the end of April, Dr. Joe Burns headed home.When the plane refueled in New Jersey, some soldiers kissed the American soil. For Burns, the smell of humidity and the sight of greenery almost made him giddy.After a debriefing in Texas, he flew to North Dakota on April 25, his 26th wedding anniversary. When the plane pulled up to the gate at Fargo, Burns' daughters, Anna and Sarah, waited, along with his wife, Becky.His gift to Becky, purchased in Kuwait, was a brass Aladdin's lamp, the kind you rub to make a wish.His own wish had already come true.Shortly before midnight, Burns arrived home. Within minutes, Becky was asleep. A teacher, she had to be at school the next day.But Burns was wired.He wanted to savor the comfort of his own bed, the closeness of his family, the quiet he had desperately missed. And the peace.Finally, he fell asleep.To be continued.