TWO inmates were killed and two seriously wounded after rival gangs rioted yesterday at Macau's Central Prison, on Coloane Island. Prison security chief Daniel Ferreira said fighting broke out at noon, while the prisoners were having lunch in a main hall. About 30, belonging to two rival triad gangs, engaged in a row that escalated into a bloody fight. Stools and eating utensils were used as weapons, seriously injuring four and wounding more than a dozen more. The four were sent to Macau Government Hospital, but two later died. The remaining two were in critical condition last night. The two dead were Lam Bing-tim, 19, and Chow Hon-man, while Wong Man-biu and Ho Wing-fai were in intensive care last night.