THE MASS Transit Railway's attempt to induce more commuter courtesy evaporated in a hectic 45 minutes yesterday when thousands poured into Central station to get home before Typhoon Tasha. MTR officials were forced to shut down escalators shortly after the raising of Signal No 8 at 4 pm to stem the flow of people pouring down onto platforms with rows of people hundreds deep. Scrums flared into violence as people tried to get off arriving trains while others sought seats. Elderly women flailed umbrellas and bags to fend off gangs of young male hot-heads. On one packed train a middle-aged American demanded non-existent space to allow room for his overweight and over-heating wife. When the train arrived in Tsim Sha Tsui, the man faced a crowd of about 200 people and yelled to his wife: ''This is not New York, Daphne, use your elbows'' before stiff-arm tackling a small Indian man who was later trampled under foot. ''Please mind the doors please,'' was scarcely audible above the melee.