When soldiers from Israel’s Unit 669 rescue squad are called to pick up wounded comrades from Gaza, the clock starts ticking immediately.

Within four minutes of an alert at their base at an abandoned kibbutz on Gaza’s borders, they must be ready to scramble. Then, as they drive over the frontier and into the battlefield, the “golden hour” begins.

According to the rough-and-ready metrics of combat medicine, this is the time window in which a badly wounded soldier must receive expert medical care to stand a chance of survival. Yet as Master Sergeant “S”, a combat medic in the 669, knows all too well, much can go wrong in those 60 minutes.

“From the moment we are in Gaza we are at risk from Hamas, even if you don’t see any of their fighters,” he told the Telegraph. “They have drones overhead that can carry grenades, and any piece of rubble you step on, or door you go through, can be booby trapped.”

Formed in the wake of the 1974 Yom Kippur war, Unit 669 combines medical expertise with SAS-level infantry prowess.

In a country that has long prided itself on not abandoning its injured, its motto quotes Psalm 50: “Call upon me in times of trouble, I will be there for you and rescue you.”

Drive through Gaza’s maze-like streets

Since last month’s Hamas massacre, it has carried out hundreds of rescue operations, many starting with an edgy drive through Gaza’s maze-like streets.

“Luckily we have a navigator who is like a human Waze (an online navigation app) that can find his way through any alley or backstreet,” says Master Sgt S.

The horrors his team often come across upon reaching their destination show that for all Israel’s military superiority, Hamas can hit back very hard.

“Our first mission was to help a team of soldiers who had been hit by an anti-tank missile – there were three of them who were badly injured, and the most critically wounded one was barely breathing,” said Master Sgt S. “We treated him for a haemothorax (an operation to clear a lung of trapped blood) and got him out within 50 minutes. During these operations, you eat, sleep and breathe the golden hour.”

On another rescue mission last Friday, a group of soldiers investigating a Hamas tunnel near a mosque were hit by a booby trap, leaving them buried in rubble.

“Four were dead, and another six had very bad injuries – limbs blown off, terrible compound fractures,” said Master Sgt S. “They were some of the worst injuries I’ve ever seen. We gave them what treatment we could, but the real goal is just to send them (within the golden hour) to trauma hospitals where they can get specialist treatment.”

Like many of the 300,000 Israeli troops involved in the Gaza operation, 30-year-old Master Sgt S is a reservist. When Hamas attacked on Oct 7, he was in the US studying at medical school; he took a taxi straight to the airport and was on duty by the following evening.

He spoke to the Telegraph from the Palmachim Air Force Base near Tel Aviv, where helicopter pilots that work with Unit 669 are also based. Among them was Major N, 37, a fellow reservist and father-of-three, who was at home with his family in Tel Aviv when the massacre began. Hours later, he was flying Israeli troops to Kibbutz Be’eri, where Hamas massacred around 100 people.

“It was a complete warzone – as we flew in, there were explosions, palls of smoke on the horizon, and bullets flying,” he said. “One of the helicopters ahead of us was shot down just before we landed. They all survived, but when we first heard on the helicopter radio, we realised: ‘this is real war’.

“We also knew that the terrorists were flooding through the towns and cities, and I was thinking: what if they knock on my family’s door?”

In the days that followed he did scores more missions, sometimes landing in football fields and hospitals. Like many other Israelis, he was horrified that the security forces had been taken by “surprise”, but took heart from playing a role in the rescues.

“I saw a lady from a kibbutz posting a picture on Instagram of some of the soldiers we had dropped off. She said they had arrived at the last second and fended off the terrorists.”

Suffered severe shell-shock

As well as physical rescues, the soldiers of Unit 669 also sometimes extend emotional lifelines, according to Master Sgt S. During the operation to save the three soldiers injured by the anti-tank missile, he said, he also dealt with another reservist, a young father-of-three, who had suffered severe shell-shock in the same attack.

“A week earlier, the guy had been living a normal life, and now here he was facing therapy for years with these horrible visions, that might stop him being a good husband and father.

“There is a protocol in these situations – you try to give people a task to get their mind out of things, so I asked him to pray for me in my future missions, as I noticed he was religious.”

Were the two still in touch? “You try not to do that right now. But maybe when this is all over, yes. And he is constantly in my thoughts.”