A couple of weeks after he told this story to Al-Monitor, members of the TMU were visiting a hospital in Manbij, where Al-Monitor was present, when an explosion shook the room. The wall cracked in front of them.

Harding, a British military veteran and the oldest in the group (known as “Pops” to most), volunteered to carry the mine, under his chin so he wouldn't survive mangled if it were to explode, to a basement of an abandoned building nearby. It wasn't the usual mission for the team of combat medics, and it certainly was not the preferred method of mine disposal.

The Syrian city of Manbij had been liberated from IS in mid-August after months of fierce fighting, and the Tactical Medical Unit (TMU), also known by its Kurdish name Yekineyen Bijiski Taktiki — a group of around half a dozen mostly Western volunteers — was approached by a local who was holding one of the many IS mines left in the city.

In September, when northern Syria was still hot enough for sand flies to bite, John Harding sat at a makeshift table of plywood and concrete bricks at a former dairy that is now a base for the People’s Protection Units (YPG). He was telling his favorite story from his second tour serving as a volunteer alongside YPG and Syrian Democratic Forces (SDF) fighting IS.

HASAKAH, Syria — In northern Syria, a group of Western volunteers is trying to bring combat medics into the fight against the Islamic State (IS).

“Don't be afraid,” a hospital worker said. It was a controlled detonation of mines nearby.

“Who says we are afraid?” said Karker, the Kurdish pseudonym for a young German TMU volunteer, calmly cradling his M-16 rifle.

The TMU had spent months in Manbij over the summer. According to Harding, now the commander, they treated several hundred wounded, around half of those surviving, he estimated, because they were treated so close to the front.

His team is different than any other currently operating in northern Syria, and not only because it is made up of foreigners.

“Most YPG units are combat-oriented. The TMU is an amalgamation of an infantry unit and a mobile field hospital facility. However, our medics will actively engage the enemy rather than wait for injuries,” Harding told Al-Monitor.

The group operates basic ambulances, but staffs them with well-armed volunteers. They train to get as close to the front as possible, which means coming under direct fire, and they provide cover as they treat and evacuate the wounded.

“We believe that superior firepower is the best preventative medicine in the battlefield,” said Harding.

But past and current members have faced an uphill battle to explain their worth in the war, he noted, saying, “It has taken a while to show people that this unit doesn't just transport the injured, but actively intervenes to stabilize and care for them before and during evacuation."

In this war, the wounded are usually thrown into any working vehicle and driven to the closest hospital for treatment. The YPG and SDF forces, still largely a cross between a guerrilla force and a militia, do not have designated combat medics.

“In the past, people have died due to wounds that should not have been fatal,” Harding said.

Michael Makuch, a TMU member from Germany, joined after fighting with the YPG and losing friends in battle. “I saw an opportunity in the medical unit because it is an important part to help not only the YPG and YPJ [Women’s Protection Units, the YPG's all-female equivalent] but also the civilians as well,” he said.

Paul Hetfield, from the United States, was quickly recruited by the TMU because of his background in pharmacology and first-aid training. “I hoped to share some of my medical experience with the hevals,” Hetfield said, using the Kurdish word for friend.

When the group is not in operation, they visit positions to provide troops with Individual First Aid Kits, which include basic items for self-use in battle such as chest seals and tourniquets.

“We aim to increase the number of combat medics, with the eventual hope of having several TMUs throughout the YPG and YPJ,” Harding said.

Currently, the TMU trains and awaits mobilization orders at its base as other YPG forces push toward Raqqa. But between Harding's learning the Kurdish language and training in medical and combat operations, the memories of Manbij haven't left him.

A child, around 6 years old, Harding guessed, had been shot through the chest. Harding applied a chest seal to the entry wound while a comrade applied a seal to the exit wound in the back. Harding held the boy down on their way to the hospital as the child tried to remove his oxygen mask and the chest seals covering the holes in his small torso.

“I had him in my lap and realized that he must have felt terrified by the strange white man holding something over his face and holding him still while his parents watched,” Harding said.

After dropping the boy at the hospital in Kobani, Harding would have usually returned to the front. Instead, he said, he decided to stay, helping the boy breathe, using a bag and air tube for over an hour as others tried to keep his heart beating.

But an ultrasound showed that the bullet had ripped apart the boy's heart, Harding explained. “He had died the moment the trigger was pulled,” he added.

Outside the operating room, the boy's mother smiled nervously, hoping for everything to be all right, according to Harding. He returned to the boy's body and helped the staff remove the tubes and wires and to clean away the blood before the parents were brought in.

The team drove back to Manbij in silence and arrived just in time to accept another casualty, Harding recalled. “The boy’s name was Hamid. I purposely avoid thinking about him because it is painful, but I see his likeness in every 6- or 7-year-old child I see,” he said.

Still, away from the front, among the memories of the last fight, Harding's team is finding opportunities to help. In late November a room full of munitions exploded at their base and killed six people.

“The new medics on the team got tested today in a real emergency situation. I'm glad to say the boys done good,” Harding posted on Facebook.