At the beginning of HSDS, Mo Dong Hero # 3 Yu Doi Nam was ambushed by Yan Yeh Wong and Yan So So after they lured him onto their ship. Yu was at a disadvantageous position because he was all alone. Originally, he had been traveling with Cheung Chui San, but shortly after they gained possession of the Dragon Sabre, they traveled separately: Cheung to settle matters with a coastal pirate that had been terrorizing people living along the coast, and Yu back to Mt. Mo Dong. What if they had traveled together back to Mo Dong? Could Yan Yeh Wong and Yan So So have successfully ambushed both of them?
Had all seven Mo Dong Heroes been together, it's doubtful anybody would have even tried to steal the Dragon Sabre.