WILLIAM BRANGHAM: Russia now claims it has won the battle for Bakhmut, but the fighting continues.

Both sides have taken massive casualties to control the symbolic, but strategically marginal city in the east of Ukraine.

John Ray of Independent Television News has this rare look from inside one of Ukraine's military field hospitals.

And the note of caution: Images and accounts in this story could well disturb some viewers.

JOHN RAY: Its location is secret, because, in the battle for Bakhmut, even this medical post is under fire, a fragile haven of humanity amid carnage.

We watch as doctors fight to save a soldier.

Half his face has been ripped away by shrapnel.

"All you have to do is breathe," says a doctor.

He tells him: "If you panic, you're dead."

There are more casualties than ever, sometimes too many to treat at once.

DR. KAPLYA, Fifth Assault Brigade (through translator): You know, I am a doctor.

I'm not God.

JOHN RAY: This is Kaplya, one of Ukraine's top trauma specialists, who leads a team of front-line medics.

DR. KAPLYA (through translator): Sometimes, I have operated on a soldier who should really have no chance to live, but, somehow, they survive.

That inspires me.

JOHN RAY: The soldier's name is Anatoly.

He's 31 years old and, for a while, his fate seems to hang in the balance.

As shells begin to land, so too does the safety of the medical unit.

Ukraine's artillery, close by, fires back.

Members of the team were injured when a Russian rocket landed outside the door.

Dimitri says it's a constant danger.

Back and forth, yes.

You fire, Russians fire.

Ukraine does not reveal the number of its soldiers killed and injured.

But the discarded bloodied uniforms reflect the intensity of fighting in Bakhmut.

This commander tells me that, in the city, his unit has been bombarded for three hours nonstop.

One of his men lies on the treatment table.

A shell exploded beneath.

He cannot move his legs.

When you witness scenes like this, it's impossible not to think about the bloodshed, the sacrifice, the loss of life.

But, for these medics, I suppose the operating table itself is a kind of battlefield, with its own defeats and victories.

The paramedics here risk their own lives, ranging across the battlefield to save others.

Why do you do this?

WOMAN: Because it's my country.

That's all.

JOHN RAY: It's your country.

WOMAN: Yes, it's my country.

I would like this country, my country, stay on the map of the world.

JOHN RAY: As for Anatoly, his condition is now stable.

Will he be OK?

Will he be OK?

DR. KAPLYA (through translator): Yes.

I feel good.

JOHN RAY: He's taken to a hospital safe, from the front line, alive, but he will bear the scars of Bakhmut forever.