Families of those killed in the Grenfell Tower fire left an inquiry in tears after a video of the blaze was shown without a warning.
One woman was said to have collapsed outside the hearing after seeing the video, which included footage filmed from inside the burning building.
An inquiry official apologised, saying a warning system had failed.
The second day has been dedicated to commemorations of those killed, including six members of one family.
A nephew of one of the 72 victims said the bereaved wanted "the truth" and "those in power" must "listen to our stories and learn from your mistakes."
Karim Mussily, whose uncle Hesham Rahman lived on the 23rd floor, earned a standing ovation from other relatives in the room when he told the inquiry: "We've been censored enough, it's our time; whether you like it or not, you have to listen."
A video about the Choucair family started with clips of the fire in which people could be seen at windows surrounded by flames and screams could be heard.
Between 20 and 30 people left the room and wails could be heard outside.
The BBC's Emma Harrison said some were in extreme states of distress.
The inquiry at the Millennium Gloucester Hotel, South Kensington, paused while the person who collapsed received medical treatment.
Bernard Richmond QC, who is leading the presentations by bereaved family members, said he was sorry a warning had not been read out before the film was shown.
He said it had been a busy day and a system the inquiry had put in place for warning of troubling material had failed before this particular video was shown.
When the hearing resumed, Mr Mussily said on a previous visit to his uncle the lift had been broken and the single staircase was narrow.
He said: "I couldn't help but think how on earth would my uncle escape if there was a fire."
Hisam Choucair, who lost his mother, sister, brother-in-law and three nieces in the blaze on 14 June 2017, had earlier told the inquiry how he could only watch helplessly as they died.
Mr Choucair said the deaths of his mother Sirria, 60, sister Nadia, 30, her husband Bassem Choukair, 40, and their daughters Mierna, 13, Fatima, 11, and three-year-old Zainab was an "atrocity".
He said he had "always had a bad feeling" about the building.
Mr Choucair said when he got to the scene the building was "completely engulfed in flames" and he simply had to "stand there for hours watching them all burn to death".
He said his mother, who arrived from Lebanon as a teenager in the 1970s, was "loving, kind and patient" while his sister and her husband, who lived two doors away from her in the block, were very popular and hard-working.
He said his eldest niece, Mierna, had an "excellent sense of humour", loved sport, music and school and wanted to be a doctor or a lawyer.
His sister Sawsam, who lived with their mother in the tower, also spoke of her grief.
She said she managed to speak to Bassem on the phone during the fire, adding: "His first thoughts were to reassure me.
"He told me everything was alright, even though he was trapped with my family in a burning building."
At the inquiry
By BBC reporter Emma Harrison
Laughter fills the room during lighter moments of the tributes, as family members recall funny stories or traits of their loved ones.
But the tears continue to flow as those reading emotional tributes struggle to maintain composure throughout their statements.
The support and empathy towards those talking is strong, and the audience shows appreciation for their bravery with applause.
As the first day had already witnessed, the common theme so far is how incomprehensible their deaths were and the need, as one family member put it, "to find out the truth".
The second day of the inquiry also heard from the husband of Maria Del Pilar Burton, who is regarded as the final of the 72 victims.
Mrs Burton, 74, who had dementia, died in January after her health deteriorated following the fire.
In an emotional tribute, Nicholas Burton said it took away her "dignity and everything we had in this world".
Mrs Burton, known as Pily, was born in Spain in the 1940s and was one was one of the very first residents in Grenfell Tower.
Mr Burton, who was with his wife for 34 years, told the inquiry she was an "extraordinary woman".
He said: "She was a unique, beautiful, exceptional person until this tragedy had taken it away."
Also commemorated were Rania Ibrahim, 30, and her daughters Fathia, five, and Hania, three, who lived on the 23rd floor of the building.
Rasha Ibrahim said her sister moved to the UK from Egypt in 2009 but the pair remained very close.
In a statement read to the inquiry by an interpreter, Mrs Ibrahim said: "It is so important for me to understand how I have lost my beloved sister while my children have lost their little cousins."
A tribute to Debbie Lamprell, a safety officer at Opera Holland Park, from her mother said the 45-year-old was "always laughing".
Miriam Lamprell said she was "bereft" without her daughter and she felt a part of her had been "ripped out".
Relatives of all 72 victims will be given the chance to commemorate loved ones during the inquiry, which will look into all the deaths.
Families are being given as long as they need to tell the inquiry about their loved ones through a mixture of words, pictures and videos.
A minute's silence was held at the start of the afternoon session to respect the anniversary of the Manchester terrorist attack.