THIN, wiry and perceptibly sharp-eyed, Ang Rita, 49, rests in his stone house at Thamo, Nepal. The undisputed master of the mountains has completed 25 Everest expeditions. And this year on May 23, the legendary Sherpa made it to the summit of Chomulungma for the 10th time. He didnt want to. He said as much to fellow climbers in Camp 2. But Goran Kropp, a 29-year-old Swedish climber who was trying to make it to the summit without oxygen, insisted, cajoled and bribed Rita to the top with a rather piffling sum of $800.