They ran over rocks; they held their breath under water. They cowered under beds and climbed trees. The details of how hundreds of young people managed to escape the dum-dum bullets being fired by Anders Behring Breivik emerged on Monday as those who survived the Utøya massacre struggled to come to terms with how close they had come to death.

Jaran Berg, a Labour party member from Østfold in south-eastern Norway, described running for safety after hearing the first shots ring out, racing between hiding places and then suddenly confronting the abject horror of Breivik's murderous activities.

"[I] come round a bend and there I see that there are bodies lying; I can't be sure how many, at least 10 young people," he wrote. "One image has burned itself into my mind: I guess she must have been 16 or 17, just lying there with a hole on the top of her head, absolutely the most horrific sight I have ever seen.

"I have to throw up, then take a moment or two to gather myself again."

Berg was not the only one to witness bloodshed on the way to safety. From a viewpoint on the pier, Kjetil Vevle, 23, saw the first shots taken by Breivik. As soon as he realised the truth – that the blond man in the police uniform was not the officer he had been expecting – he ran. He hid first in a bush and then in a small room in the main hall, then found himself running past a person who had been shot.

"On the road, I saw a shooting victim lying down and bleeding. But none of us were in any condition to help someone who bleeds so much. And we heard shots behind us. So we just had to continue," he told the Aftonbladet newspaper.

Having reached the south-west of the island, Vevle eventually hid in a hollow in the rock for what "felt like many hours". "I hear the shots being discharged closer and closer now … it feels as if the gunman is standing right over the spot where I was sitting. I say to myself that it's over, now my end has come."

Vevle, like many of his fellow camp participants, sent a text message to his parents saying he loved them. "I was in no doubt it was the last time they would hear from me," he said.

Hiding under a bed in a woodland cabin, Vegard Geroslaven Slan, also feared the worst. He told the BBC he saw "people fall to the ground" and be shot "in the head" by Breivik. "We were a group of almost 40 people hiding in this cabin and we could hear gunshots all the time," he said.

"I knew he was going for the kill. It was terrible because I was thinking that he was shooting my friends while I was lying there but I was just praying and hoping that he wouldn't come into the cabin where we were and, thankfully, he didn't."

Not all the survivors were able to hide. In a remarkable witness account, an 11-year-old boy was said to have confronted Breivik and told him: "Don't shoot me, you've been shooting enough. You've already killed my dad. I'm too young to die."

The account, told to NRK, the Norwegian state broadcaster, by 21-year-old survivor Adrian Pracon, has not been independently verified. Pracon himself, who was shot in the shoulder by Breivik, said he managed to avoid being killed by lying still and feigning death.

After a terrifying wait for the shooting to finish, Berg emerged from his hiding place to find a policeman shouting "Hello, is anyone down there?" Having been shaken by Breivik's uniform, he was unsure what to think. "I went gingerly out, still shaking from nerves, look up, straight into the face of a policeman," he wrote.

"He's got his weapon trained on me and shouts that I should put my arms up. I do so, hoping that this is the real police. And, thankfully, it was."