21.1公里 汀九, 汀九橋 (第3折返點) 2小時40分 10:40, this may be wrong. As now the finish point is in Causwaybay Victoria Park and in last two years ago, the second turning point is also 21.1km at the 汀九橋 (第3折返點). and in the past the finish point is at Wanchai Convention Centre ( Gold ??? ??? Plaza- do not know the English name).
Therefore the 3rd turning point should be shorter than 21.1km.
For those who take 5:10 to reach the 39.2km, most likely is not running any more. They are all walking only. Walking 3km at 20 mins is FAST considering after 39km. Therefore, if you don't reach 39.2km at 5:10, you almost have no chance in meeting 42.195km at 5:30.