Apparently, Myuu noticed the state of Lemia’s legs from over Lemia’s shoulder. Both of her feet peeking from Lemia’s long skirt were bandaged all over, they were in a miserable state.
This was the thing Saluz talked about, and it was what Hajime’s party heard from the young man on their way to Elisen. The thing that made the Sea-dweller tribe agitated was not only was Myuu kidnapped, but also how her mother was seriously injured that it became impossible for her to walk.
Though Myuu said she was kidnapped when she was separated from Lemia, the Sea-dweller tribe wouldn’t be able to say it was a kidnapping unless there’s an eyewitness. They were able to declare so because it seemed Lemia had actually encountered the kidnappers.