Unlike with the others, she didn't rely on her hearing. She kept looking back to make sure that he was still following. A lost nicheling couldn't be trusted to keep up on their own. She had to stop multiple times because he kept looking around.
At least he's showing interest towards the world around him. Perhaps he remembers this place? Maybe there's still hope for him?
As they got to the swamp clearing she realised that she wasn't going to have a moment to try and explain everything to him. There were other nichelings at the swamp, just behind the reeds.