A 19-YEAR-OLD inmate freed himself from handcuffs and jumped nine floors to his death at a hospital while a prison officer left him unguarded to answer a telephone call. A coroner's jury yesterday returned a verdict of death by suicide in the case of Wong Ka-fai, an inmate of a drug addiction treatment centre. Wong died of multiple injuries on May 23 after he plunged from a window in a ninth-floor ward on to the balcony of Queen Elizabeth Hospital's canteen. Coroner Warner Banks heard that Wong was serving a detention order at Hei Ling Chau Drug Addiction Treatment Centre after he was convicted of theft last December. Wong, who claimed he had suffered from asthma since he was nine, first attempted suicide on May 3 by slashing his left wrist with a piece of broken glass. He told the doctor who examined him that he wanted to end his life because he could not tolerate the pain of an asthmatic attack. However, physical examination revealed no asthmatic attack. He was sent to the Siu Lam Psychiatric Centre for mental assessment. Eighteen days later, Wong was transferred from the psychiatric centre to Queen Elizabeth Hospital after he experienced difficulty breathing. Unemployed Shek Pui-yeung, a patient at the hospital, said Wong was lying on a bed next to his the afternoon of his death. He recalled that a nurse told a prison guard to answer a phone call. Soon after the officer left the ward, according to Mr Shek, Wong managed to free his right wrist from a pair of handcuffs which had been secured to his bed. ''He pushed open the window, climbed up on the bed and jumped out. It all happened in a split second,'' Mr Shek said. A doctor rushed to the scene and found that Wong had no sign of life. Chan Ho-shing, an assistant officer from the Correctional Services Department, said he took over the guard duty of Wong from his colleague at 1.10 pm on May 23. The court heard Wong had been handcuffed on his bed since his admission two days earlier. At 3.40 pm Mr Chan went to a corridor outside the ward to answer a phone call, leaving Wong unguarded. Mr Chan heard someone shouting from the ward a few minutes later. He rushed back and found Wong was missing. After the hearing, a spokesman for the Correctional Services Department confirmed the department had carried out an internal investigation but said the officer was not subjected to any disciplinary action. ''We found no loopholes in procedures in handling inmates who seek medical treatment in an open ward,'' the spokesman said.