Let us go back in time...
Xu Xiaoshou headed straight for the mountains without stopping after he parted with Mu Zixi.
Possessing the Agility Skill of the Master Stage meant that he could traverse the entire length of the Inner Yard within mere seconds, and could travel at hair-raising speed to his new home in no time at all.
He then put his long-range surveillance plan to work.
As he had upgraded his Sense Skill, he could easily see everything the three were up to in the mountains. He not only saw what they did but could hear everything said, to the extent of even hearing their noses snorting. He assessed their tones and observed their body language.
Xiao Qixiu made his appearance almost at the same time as Xu Xiaoshou did. The masked man had stabbed Xiao Qixiu effortlessly when they last clashed. Thus, he speculated that the masked man would dispose of the Elder Xiao just as quickly.