Transcript for Eyewitness shares details from Manchester attack

We are joined by Joseph Harries at the concert last night. Thank you for joining us. Just take us back to that moment. What did you see? What did you hear when that blast went off? It just panic and hysteria to be honest, George. People were screaming, people were running. To be honest, peoply just trying to get out of the arena as far as they could. You were inside the arena? I was. I was directly in front of the stage at the heart of the arena as you would. I had exactly the same distance to get out of any of the doors. Did you have any idea what happened? I -- when it happened I had no idea. I thought perhaps there was a malfunction in some of the technical things because obviously there was lighting and lasers and everything throughout the show, however, once people started screaming and running back into the arena, I gathered sort of a prospect as what happened. People were running back into the arena. You were trying to get out. What did you do next? Well, I had my best friend with me. I grabbed hold of her wrist and told her to never let go of me in that moment. We just ran and jumped over chairs, railings to try to get out of these doors. We had to force open some doors that wouldn't open and because people were trying to get to the entire capacity of the 21,000-person arena was trying to get out of one exit which had been allocated by the security themselves, which was with a load of preteen boys and girls, it was a recipe for disaster from the beginning? How long did it take you to get out and what did you see when you got out of the arena? It felt like an eternity to be honest. It couldn't have been more than two, three minutes until from in our seats to outside of the arena itself, however, it felt forever. We tried our hardest to get past because obviously in that moment you obviously can serve people around you however you're your main priority. As long as you're safe and you're fine in that minute it's good with you and when you find what you're looking for at the end and when you find out like I did myself about the injuries and the fatalities, it really dawns on you. So you didn't see any of the injuries or fatalities when you left the building. Not personally I didn't. However, my friend did who was also in the concert that evening. He lives here in Manchester and he was there with one of his friends and he had told me he had seen some -- a girl covered in blood and she had bandages around her neck by paramedics outside. He said it was traumatic and horrendous experience for him. When did you know you were safe? The minute I got back to my hotel. Until then even walking out, walking out the arena surrounded by people, you get into this sort of instinct feeling where you're not safe until you are sort of enclosed in your own personal environment. We're glad you're okay. Joseph, thanks for joining us this morning. Thank you very much. He was so clear-headed in such a disorienting time and learning the name of one of those killed. Regina calendar from Renshaw college in England. You see her there with Ariana grande.

This transcript has been automatically generated and may not be 100% accurate.