CHINESE badminton player Zheng Yumin, who collapsed during the finals of the Asian Team Championships last week, left Queen Mary Hospital yesterday but will remain in the territory for further tests. Zheng shocked a live television audience and a 3,000-strong crowd at the Queen Elizabeth Stadium when he collapsed during the men's doubles final. He received mouth-to-mouth resuscitation and cardiac massage after losing consciousness. He is thought to have had an epileptic fit. Mr Edwin Leung, a friend of the Zheng family, said: ''The doctors who attended to Zheng has failed to pinpoint the cause of the incident.''