Su Yang was unaware of Ge Kaiyang's plan to ambush him; he didn't even know about the internal strife within the Four Major Sects.
After leaving the southern Paradise territory, he didn't have a place to go temporarily, so he traveled with Lv Donglin towards Capital City.
All of this was within the Jade-faced Judge's speculations.
Of course, there was another reason Su Yang chose to go to Capital City, and that was that the people from the Four Major Sects were not in Capital City right now. It was temporarily still safe over there, so going would not pose any danger. Hence, Su Yang wanted to witness the battle between Qi Zhishan and the Martial Champion.
