Dr Maksym Balaklytskyi flinches at the sound of a military jet flying high above the University of Essex campus.
He struggles, briefly, to explain in English why the sound haunts him and plunges him into a state of heightened readiness.
Before the Russian invasion of Ukraine in February 2022, Dr Balaklytskyi was a professor of journalism at the University of Kharkiv, in eastern Ukraine.
For days he, his wife Iryna, 37, and their 10-year-old son Nazar sought safety in the basement of their city home.
Dr Balaklytskyi saw a missile explode in a neighbouring block.
"It was an apocalyptic picture, like from Hollywood," he says. "There was a sense of fear, but the most unpleasant thing was a sense of total uncertainty.
"You don't know what to expect, or how to react, what the actual dangers are or how to prepare for anything."
After six days of bombardment the family fled Kharkiv.
Iryna, who taught medicine at university, and Nazar crossed the border into Poland, but Dr Balaklytskyi stayed in Ukraine - until February this year when he and his family were finally reunited in Colchester, Essex.
The family are now among the more than 160,000 Ukranians who have settled in the UK as a result of the Russian invasion.
Dr Balaklytskyi, hoping the war would be short, had stayed in the western Ukrainian city of Lviv where he covered the impact of the invasion for a church-affiliated television station.
Working "gave me a sense of belonging, a sense of purpose that I was contributing to something important," he says.
In an effort to cope with the separation from Iryna and Nazar, Dr Balaklytskyi threw himself into running, cycling and swimming.
"The separation was painful and completely uncertain," he says. "Nobody knew what to expect.
"The leading reason for evacuation was to spare the life of our son."
Iryna and Nazar went first to Poland and then to Utrecht, in the Netherlands.
But Iryna, a doctor, found that in order to work using her medical skills she would need to pass the state exam in Dutch.
With a working knowledge of English, she then applied to live in the UK via the Homes4Ukraine and found a family sponsor in Colchester, with whom she still lives.
The family stayed in contact by phone and Dr Balaklytskyi would send videos and pictures of "everything worth talking about".
Almost a year after the family's separation, Dr Balaklytskyi, who, as an academic was exempt from military conscription, was allowed to leave Ukraine to be with his wife and son.
He says he did not know whether "to jump, dance and cry out of joy or to kneel down to pray".
"A waterfall of thoughts and emotions roars in your head," he says. "Then you understand that a new, unknown, life has just begun. It is then we all cried and cheered on the phone the most."
The reunited family currently lives just outside Colchester with their hosts.
Although they were offered two rooms, the trio have chosen to share a single room together.
"For me, it is a real miracle that God, despite all the obstacles, reunited our family," says Iryna.
"I really missed Maksym and our past life we were a part of.
"I fell asleep and woke up with the thought and prayer for family reunification.
"It was very difficult to make difficult decisions alone. It is hard to travel alone with a child through all these countries. It's hard to raise a son alone."
Dr Balaklytskyi has joined the University of Essex's history department where he will study the evolution and impact of Russian news and propaganda.
He will also be looking at what he sees as the formation of a more unified Ukrainian identity as a result of the war.
Praised on his English by King Charles III during the monarch's recent visit to Colchester, Dr Balaklytskyi tells of a complex modern Ukraine with numerous regional identities and histories.
He says while significant numbers of people, particularly in eastern Ukraine, were traditionally more aligned with Russia and distrustful of the west, the invasion had forced "everyone... to reformulate their attitudes".
Dr Andrew Priest, head of the university's history department, says: "As an internationally diverse university and a university of sanctuary, with a long-standing commitment to human rights, support for and collaboration with colleagues from countries affected by conflict and other forms of crisis is at the heart of what we do, and who we are."
While Dr Balaklytskyi begins his work with the University of Essex, Iryna has found employment as a nurse at Colchester Hospital and Nazar is in school.
"Now we are happy to be together," she says, despite the huge changes in their lives and situations.
"When [we lived] in Kharkiv we had good jobs and lived in our own apartment. Everything was familiar and understandable," he adds.
"But the main thing is that we are together now."
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