Anyone with experience moving through the wilderness knows that it's easy to lose your way once you enter a forest. This is because it's impossible to walk in a straight line. After all, trees and vegetation are everywhere, and you have to go around them when you encounter them.
After detouring a few times, your sense of direction becomes a complete mess. Fortunately, the sun was in the sky, so it wasn't impossible to find their direction. This forest wasn't on the map, which was probably because the map was too old.
So the three of them discussed it and decided they couldn't head west to chase after Ning Xian'er and the others. It was already very difficult to track footprints in a forest, and with the extremely dense vegetation, the three of them were afraid they might wander into a bewildering forest.
Therefore, the trio turned south, planning to follow the direction the people of the Southern Frontier had taken, which Qin Yan had inquired about. They would ask for more information when they reached the next town. And so they walked, for an entire morning, yet they still hadn't left the forest.