Occasionally, a protest image goes much further than documenting a moment. It clarifies an injustice.

The piano in front of a wall of riot officers at Kiev’s Maidan. The woman in a red dress being teargassed in Istanbul. Tank man on Tiananmen Square.

No one knows just how significant last Saturday’s protests in Moscow will prove to be. The fierce police response, and 1,300-plus violent arrests have already left an impression. But perhaps the most enduring watermark will be Russia’s own red-dressed woman: the moment Inga Kudracheva, 28, throws herself onto her boyfriend of two years Boris Kantorovich, 27, to protect him from the blows of police truncheons.

With every swing of the baton, the couple seem to hold each other tighter. In the foreground, alsatian police dogs howl with intent. Kudracheva screams for onlookers to intervene. The police seem confused and pursue a chaotic strategy of intermittent clobbering and pulling the couple apart.

Eventually, they drag the pair across the granite pavement, an expensive symbol of Moscow’s urban beautification, ripping Kudracheva’s red dress in the process.

March of maternal anger in Moscow: in pictures Show all 9 1 /9 March of maternal anger in Moscow: in pictures March of maternal anger in Moscow: in pictures Police officers detain a protester during a protest against the treatment of a female political prisoner in Moscow on February 10 Reuters March of maternal anger in Moscow: in pictures A woman holds a stuffed toy during a protest against the treatment of a female political prisoner in Moscow on February 10 EPA March of maternal anger in Moscow: in pictures Protesters scuffle with police officers during the march of maternal anger in Moscow EPA March of maternal anger in Moscow: in pictures A woman holds a copy of Russia's constitution during a protest against the treatment a female political prisoner in Moscow on February 10 Reuters March of maternal anger in Moscow: in pictures A protester waves a sign at the march of maternal anger before being detained by police in Moscow on February 10 Reuters March of maternal anger in Moscow: in pictures Police officers detain a protester during a protest against the treatment of a female political prisoner in Moscow on February 10 Reuters March of maternal anger in Moscow: in pictures Protesters march in Moscow on February 10 Reuters March of maternal anger in Moscow: in pictures Police officers detain a protester during a protest against the treatment of a female political prisoner in Moscow on February 10 EPA March of maternal anger in Moscow: in pictures A woman holds a stuffed toy as she marches against the treatment of a female political prisoner in Moscow on February 10 EPA

The meaning of Inga and Boris’s moment required no translation. It was the triumph of love over violence. It was non-violent resistance. It was a switch that turned police cyborgs into absurd caricatures of autocracy.

The vast majority of the millions who watched the footage will have had little idea about the details of the scandal surrounding Moscow’s city elections, planned for September. But the dramatic images gave an immediate understanding of the stakes.

In an interview with The Independent, the advertising executives turned protest icons say they had no idea the rally would change their lives.

Kantorovich says there was a sense things might get uglier than usual. There had been warnings of violence in the run-up, he said, and authorities had shut down much of central Moscow the night before.

“When we woke up that morning, Inga said she felt like we were going to war. Of course, we knew it wouldn’t be a summer stroll.”

Kantorovich warned his mother to stay away. But together with Kudracheva he headed for the epicentre of the protest near the mayor’s offices. There, it didn’t take long for things to take a bloody turn. Kudracheva, a trained first aider, made her first headline of the day, bandaging up the bleeding head of a municipal lawmaker.

Kudracheva says she routinely carries bandages, gloves and antiseptic in her bag. In protests, she says, it it is especially important to calm down the crowds: “That’s really what the gloves are there for. To take control and provide psychological assurance.”

There would be more bloody clashes all around town, but the most dramatic confrontation was sparked when the protest moved to Lubyanka Square, the imposing home of Russia’s security agency.

It was not immediately clear why authorities allowed the crowds to come so close to such a sensitive spot. But Kantorovich was one of the first to find out what they felt about such a development.

For Kantorovich and Kudracheva, the fear is that the authorities will now seek revenge for their act of civil disobedience (Oliver Carroll)

They hit him so hard – on his head, on his arm and back – that one of the truncheons broke.

“You could see the officer was consumed by hatred and fear,” he said. “But you could also see he was startled by Inga’s response – as I was.”

Kantorovich, who is still covered in bruises from Saturday’s encounter, reaches out a hand to his girlfriend.

“We have very different stress responses,” he says. “I get chatty. I just can’t stop talking. But Inga goes quiet. She switches to action mode.”

Of course we are fearful. But we’re not going to shut up. After Saturday, that moment has passed Boris Kantorovich

Kudracheva said she remembers nothing about the chain of decisions that saw her first run towards her boyfriend and throw herself on him.

“I didn’t feel or think anything,” she said. “I think that even if they had only tried to arrest him I’d have done everything to get him back.”

“Non-violent resistance” will become a major part of the protest tool kit in the weeks to come, she added. “You saw how they responded. They lost themselves. They didn’t know what to do.”

Russia’s protest movement has developed quickly in the space of a few weeks. The focus also seems to have shifted from the narrow issue of participating in September’s city government elections, to wider democratic demands.

Both sides have drawn battle positions. For the protesters, it is about the principle of unrestricted and fair elections, chiselled away over the last two decades. The Kremlin seems equally as concerned about averting the possibility of coloured revolution.

Kantorovich says the Russian authorities overestimate the revolutionary aims of protestors.

“They seem to think we will move to the Kremlin and start throwing Molotov cocktails,” he said. “We aren’t even close to that, and I hope it won’t happen. But the Kremlin is making the problem worse for themselves with some very stupid decisions. It’s as if the clever ones are away on holiday.”

On Friday, Moscow city authorities announced it had agreed to a proposal to hold a 100,000-strong protest rally just outside the city centre on 3 August. At least part of the opposition will insist on more central venues, however, raising the prospect of another violent confrontation.

For Kantorovich and Kudracheva, the fear is that the authorities will now seek revenge for their act of civil disobedience, perhaps with the threat of an unfounded criminal prosecution. This, after all, was a road the Kremlin went down after protests in 2012 and seems to be proving the way in 2019 – with mass arrests and night-time raids of opposition leaders.