Lucy and Lith heard some cries. They were more of a whimper. Lith wasn't able to tell what sort of cries they were and could only stealthily go towards the source.
Lucy knew full well what those whimpers were but she didn't say anything. It was Lith's adventure and she was only testing him by asking questions and was mostly on the side watching him do his thing. She enjoyed watching him fight and be cautious of some stupid trap which wouldn't even hurt him. She would internally laugh at his silly sneaky walks to avoid traps.
Lith was very inexperienced and he could only try his best to apply whatever knowledge he knew into practice. He was slowly but surely having practical knowledge too. He knew what to do and what not to but while he was actually into doing it, he looked silly as he was inexperienced and his movements weren't very flexible.