Kharkiv, Ukraine CNN  — 

Just before the start of Alexandra Rudkovskaya’s shift on Saturday, her mom gave her a big, long hug. The kind mothers give their kids when they don’t know when – or even if – they’ll see them again.

Rudkovskaya, 24, works as a paramedic in Kharkiv – a choice she says leaves her mother “worried to the point of hysteria.”

“She says you need to leave this town, you need to go to some place safe. Why do you need to do this? I have only one child, stop doing this,” Rudkovskaya told CNN.

Just hours after their hug goodbye, the stuff of her mother’s nightmares came true when Rudkovskaya and her partner Vladimir Ventsel put their lives on the line to reach an injured patient. CNN was there to witness their bravery.

Kharkiv, which is close to the Russian border in northeastern Ukraine, was one of the first cities to come under attack when Russia invaded two months ago. It has been subjected to near-constant shelling ever since.

Rudkovskaya hugs her mother at the start of her 24-hour shift.

As first responders in the city, Rudkovskaya and Ventsel find themselves running towards danger – even as everyone else is fleeing – on a daily basis.

They know they have to work fast. Russian forces have increasingly been terrorizing the city with so-called “double-tap” strikes: Hitting a target, waiting a few minutes for the first responders to arrive, and then hitting the same spot again.

When they hear the deep thuds of a bombardment early in their shift on Saturday, Rudkovskaya and Ventsel are on standby for an emergency call. Moments later, they get one. At least one person has been wounded in the shelling.

Rudkovskaya, Ventsel and their driver jump into their ambulance and set off. Each has a flak jacket, but they only have one helmet between the three of them.

Ventsel approaches an apartment complex that was struck.

Just moments after they arrive at the site of the first strike, the whole place starts shaking again. The building next door has been struck. The loud booms of several explosions are followed by the sound of shattered glass.

Rudkovskaya and Ventsel know what to do. They run down the darkened entry hall and hide at the bottom of the stairwell, waiting for the worst to pass. Ventsel tells the CNN team to cover their ears and open their mouths to avoid damage to their hearing.

While this is happening, the team struggles to locate the wounded person they were called to help. Ambulance crews in Kharkiv rely on cell phones for communication, but signals get disrupted whenever there’s a hit – which is often.

“We are without connection and they are shelling the sh*t out of us,” Rudkovskaya says.

Once she is able to get through, she shouts into the phone: “Tell me your damn house number.”

“12G,” says the desperate voice on the other end of the line. “I repeat: 12. Gregory. I’ve told you a thousand times,” the caller says in desperation. “The man is dying.”

As a barrage of rockets rains down on the area, the CNN team has no choice but to run for safety. Rudkovskaya and Ventsel run back inside.

Moments later, they manage to find the victim, a 73-year old man who has suffered shrapnel wounds and head trauma. The bandages around his head are covered in blood and he gasps when the medics move his arm, but the rescue workers say he will survive.

Ventsel asks about the pain but the man only points to his ears. He’s been deafened by the blast and can’t hear. The pair stabilize him and rush him into the hospital.

Ventsel prepares to transfer the injured man to hospital staff.

Rudkovskaya and Ventsel, 25, work for the Center of Emergency Medical Care and Disaster Medicine in Kharkiv Region.

They say the organization has been stretched thin since the start of the war. Some of its employees opted to leave Kharkiv when the invasion began, and the service has suffered significant material losses in Russian attacks over the past two months.

The center’s director, Victor Zabashta, says 50 of its 250 ambulances are out of commission after being hit by shrapnel.

Rudkovskaya and Ventsel are deployed in Saltivka, a district in the northeastern outskirts of Kharkiv.

The neighborhood is among the hardest-hit in the region and a current target of Russian bombardment. many of its apartment buildings, shops, and even the local school have been destroyed. Parts of the neighborhood have also been cut off from basic services like water and electricity.

But despite the heavy fighting, many of Saltivka’s residents are determined to stay put. When their neighborhood is bombed, they sweep up the broken glass, tidy up and get on with their lives.

Most are elderly and have nowhere else to go, according to the paramedics.

“When we offer to take them to the hospital or some place safe they say, ‘We don’t want to go, we will stay here, this is our house.’ And they stay there. We still have people living in Saltivka, we don’t know how,” Rudkovskaya says.

Like many of those they help, the pair, too, are adamant: They are not going anywhere.

“What else did we spend six years studying for?” says Ventsel, who has a two-year-old son. “You feel an obligation to help people who are left here.”

Back at base later, Rudkovskaya and Ventsel get on with their job. They are only halfway through a 24-hour shift. The rear window of their ambulance has been blown out by the explosions. They need to clean up the shattered glass and get the vehicle ready for their next patient

“This is normal. It’s our work … It’s scary, but we’re still alive, thank God,” Rudkovskaya says.

She has been with the ambulance service for five years, and Ventsel has worked here for seven, but nothing prepared them for the horrors of working in a war zone.

“At the beginning of the war we didn’t understand how to do this work, because they were shelling non-stop and there were a lot of wounded people,” Rudkovskaya says.

“We had a woman with a hole in her chest. And we ran and helped. It was very scary. It was outside, open space, they started shelling and we didn’t know where to run and what to do because there’s no cover.”

There is no room left for feelings, Ventsel says, you simply have to get on with it. “When you are there, in that moment, you must do what you can. No emotions. You do your job and that’s it,” he says.

And he says he is determined to keep going. “We will keep doing our job until the end,” he says. “And then after the war too.”

Correction: This story has been updated to correct the spelling of Vladimir Ventsel's last name.