Police have made a dramatic rescue of a cryptocurrency trader who was kidnapped by suspected triad members and held at a house in northern Hong Kong for nearly a week as his captors tried to extract a HK$30 million (US$3.85 million) ransom from his family. Police raided the residence in the New Territories after being contacted by the family, and just as officers were swooping on the location, the trader managed to climb out a window and drop to the ground, the force revealed on Sunday. But the kidnappers had beaten the victim, 39, with hammers in their unsuccessful attempt…