That 黄尸 ocupied Central is not really gainst CY, rather than  Chinese Gov.   
CY fighted   黄尸 for  Chinese Gov. Now,  黄尸 got into 立法會. 
If CY steps down, this means that Chinese Gov. give up to   黄尸. 
This is impossible. Simple logic !!
胡须曾 gets support from 黄尸's mediam or  white or black 黄尸. That  makes him impossible.