Video report by ITV News Correspondent Martha Fairlie
Convicted terrorist Usman Khan seemed "a little shy" and did nothing to raise suspicions in the minutes before he stabbed two people to death, an inquest jury has heard.
Cambridge University graduates Jack Merritt, 25, and Saskia Jones, 23, were killed by Khan at a prisoner rehabilitation conference near London Bridge on November 29, 2019.
Barrister Catherine Jaquiss, who shared a table with Khan at the Learning Together anniversary event, said he had described how he had been going down the wrong path in life but had changed his ways.
Ms Jaquiss told jurors at Guildhall in the City of London on Tuesday, she had invited Khan to come and sit at a table to take part in a group discussion during a workshop.
When asked how Khan seemed, she said: "Perhaps a little shy. I didn’t notice anything out of the ordinary at all at the time."
Ms Jaquiss added: "I remember him saying something to the effect of he had been involved with a group of people who had been leading him down the wrong path.
"He had now seen that way was wrong and he was now essentially turning the other way or going a different way."
She said that after a refreshment break at the end of the workshop, she heard screaming and grunting coming from downstairs in the building.
The barrister, who knew Mr Merritt from her previous involvement with Learning Together, told the jury a man came into the room "who said there is a man downstairs with knives and a bomb strapped to him".
"I was certainly very scared and I suppose frozen to the spot a little bit, not knowing what to do."
Film-maker Amy Coop, who was in the Banqueting Hall to get footage of a feedback session when she heard screaming and shouting.
She described hearing screaming and sounds like a "loud and guttural roar...like the kind of thing you see in a film".
She said the sounds made her quickly realise "something very bad had happened".
Ms Coop had been attending the Learning Together conference to make a film for the organisers.
At the inquests into Mr Merritt and Ms Jones’s deaths on Tuesday, Ms Coop told the jury: "There was more screaming and shouting and it very quickly became apparent that something very bad had happened.
"As soon as I stepped out on to the landing it was clear that something was going on.”
She saw Ms Jones lying injured on the stairs, with a man kneeling next to her, trying to give first aid.
Ms Coop said: "She looked very, very unwell."
"She was ashen, grey in the face. Her eyes were open and very glassy and staring straight upwards," the film-maker added.
Ms Coop went to look for a first aid kit or something that might help reduce the bleeding for anyone who was injured.
As she returned to the landing, she heard more shouting, including "a loud and guttural roar".
She told the jury: "It was a horrible noise coming from someone. It sounded like the kind of thing you see in a film."
Khan, 28, who was armed with two knives and wore a fake suicide vest, was tackled by members of the public with a decorative pike, narwhal tusk and fire extinguisher, and then shot dead by police on London Bridge.
Earlier, jurors were shown graphic footage of Khan lying on London Bridge after he had been shot for the first time.
The 28-year-old could be seen rolling around, removing his jacket and gloves, while officers kept members of the public back.
Around eight minutes after he was first shot, he sat up, leading police to shoot him again. Less than two minutes after the second shots, he stopped moving.
Jury inquests into the deaths of Mr Merritt and Ms Jones are taking place before coroner Mark Lucraft QC at Guildhall in the City of London.