Dr Darah Burke had been crossing the foyer with his wife, Ann, and 10-year-old daughter, Catherine, when Salman Abedi detonated his home-made rucksack bomb in the City Room as an Ariana Grande concert ended.
The explosion sent thousands of nuts and bolts flying, shredding everything in their path and killing 22 bystanders and injuring hundreds of others.
Dr Burke, from Ashton-under-Lyne, Greater Manchester, told the inquiry: “Basically there was a loud bang – very loud – and I was kind of thrown forward slightly.
“I went into a crouching position. Everything seemed quite dark, almost debris in the air.
“Ann was standing up, but not straight. Catherine was on the floor. Catherine was screaming.”
Dr Burke suffered a shrapnel injury which fractured his right leg, and his wife had shrapnel injuries to her thigh and a deep wound in her heel.
Their daughter suffered 16 separate shrapnel injuries to her arms and legs and permanent deafness in her right ear.
All three had attended the concert and decided to leave as it ended to try to beat the crowds.
After the blast, Dr Burke and his wife got their daughter out of the foyer on to a link-bridge leading down to Victoria railway station.
He said: “Catherine was saying she could not see, her eyes were screwed tight. She had a lot of blood on her right side, upper limb and lower limb and head.
“Catherine was responding so I knew she was breathing and not in immediate danger.”
Dr Burke left briefly to go back into the City Room but, due to his own injuries, was not able to assist.
He helped an injured man back out on the bridge and directed police and other emergency responders who were trying to assist him to others who were more seriously injured in the foyer.
His daughter was carried by a policeman to a triage area outside the railway station and the family were eventually taken to hospital.
Earlier, Sarah Nellist told the hearing in Manchester that she saw Abedi in the foyer as she waited for her 17-year-old daughter and six-year-old niece to leave the gig.
Ms Nellist, from North Wales, said: “I just saw him stood there. He just looked odd. It was in the corner of my eye. He detonated the bomb.
“The only way I can describe it, it was like black powder paint. A high-pitched sound I have never experienced anything like before, and the heat was just unbelievable.”
Paul Greaney QC, opening the hearing after the Easter break, warned that some of the evidence to be given will be highly traumatic.
He said survivors have described a scene of youngsters giddy with excitement, feelings of joy and happy faces, and excited little girls having the “time of their lives” contrasted with the “horror shortly after”.
The public inquiry is looking at the events around the bombing on May 22 2017.
The hearing was adjourned until Tuesday morning.