Three coincidental factors

"Yes, luck," said Shao An. "There was luck involved, and by my guess, the manor are likely to be unaware of it.."

"How so?" asked Ren Shu, his interest piqued just as Yang Qing's was.

"From the account of that sixth stage palace realm expert, he and the 'friend' he murdered ventured into the battlefield, desperate for fortune since both were in the twilight of their years, with little signs of improvement. So they decided to look for rare fortune and encounters to try and alter their fates and that led them to the Banyan Empire battlefield," Shao An patiently explained. 

"But as desperate as they were, and as appealing as the Banyan battlefield was, they had grossly underestimated how dangerous the place truly was.