A Kurdish asylum seeker, Benham Satah, said guards fled when the shots rang out.
“There was nobody inside and they just left us alone. It was just us and we were thinking that we are really going to die.
“The moment that there was no officer and no staff inside, I was preparing myself for death.”
The PNG police force said the soldiers went on a rampage through the centre, assaulting police, immigration officers and service providers as well as damaging vehicles.
The police commander on Manus Island, senior inspector David Yapu, said the naval officers had been drinking.
“Those that were involved in the incident were drunk. Their conduct is unethical and unacceptable and it really tarnished the reputation of a disciplined organisation,” he said.
The member of parliament for Manus Island, Ronnie Knight, said while the naval officers were drunk their reaction was predictable.
“It happens, this is Papua New Guinea. I’m not saying anybody deserved it but you know that if you assault a uniformed officer in a naval base in any country in the world there’s going to be repercussions.”
Satah, who witnessed the murder of detainee Reza Barati when a mob stormed the detention centre in 2014, said nobody at the centre was safe.
“It is not safe even for the citizens of Australia, the staff who work here. There is no safety and guarantee for anybody,” he said.
“After witnessing the murder of my room mate and testifying in court and being through lots of threats, personally I never feel safe here.”
Yapu said police had launched an investigation and the shooters would prosecuted.
He said police and naval commanders had a meeting following the Good Friday attack and that normalcy had returned to the detention centre.
More than 600 have detainees signed a letter to the Australian government, however, requesting they be moved to safety.
“We who have been detained on Manus Island for about four years against our will are requesting to be moved to some safe place,” the letter said.
“We’ve been under military attack by machine guns and are worried about our safety in the centre. Our lives are in danger.”
Kurdish journalist and detainee, Behrouz Boochani, said the attack proved the centre was not safe.
“A lot of Australian and New Zealand staff have been traumatised by the attack,” he said.
“How does the Australian government claim the refugees are safe when they cannot even protect their own citizens?”
The Australian Department of Immigration and Border Protection did not respond when asked if it had confidence in the safety of Australians and other foreign nationals who work at the centre.