THIRTEEN inmates of Pui Yin Juvenile Home in Ma Tau Wai smashed up their room after another boy was not allowed to go to a doctor. The trouble followed a fight last month between mainland and local factions at the home as a result of a quarrel over TV channel selections. Sources said the latest incident started on Sunday night when one of the boys reported feeling unwell. A request to see a doctor was rejected by the social workers, who believed the boy was faking. A source said police were called when the boys started ''smashing up things in the room, including the drawings hanging on walls, boxes, light switches, blankets and pillows''.