An elderly man surrendered to police after he locked the metal gate of his ex-lover's flat in Sha Tin with a bicycle chain, poured thinner on the wooden door and set it alight at about 3.45pm yesterday. The woman, aged about 60, and her two adult sons were inside the flat in Greenwood Garden. Firefighters rescued them. The trio were taken to hospital. The man, aged over 70, was being held for questioning last night.