The passages within the underground ruins were intricate and complex, resembling broken meridians. Yusuf Zuck simply didn't care where he would end up running nor was he concerned about potential dangers, as they could not surpass the immense peril posed by the four Earth Immortals.
Also, Yusuf found that within these subterranean passages, his Telekinesis was hindered. Even his thoughts could only extend a mere two to three meters.
Beneath the land of Saint Dragon, all Divine Sense is isolated. This is the mystery of the Saint Dragon Continent, so even after you enter the underground, you still cannot use Divine Sense to detect anything.
Yusuf had been running for about half an hour, clueless about his current whereabouts. Clearly, the four Earth Immortals hadn't caught up, and even if they entered the underground now, it would be nearly impossible to find him given the maze-like corridors.