Still doesn't meet any definition (quoted earlier from Wikipedia) of cliffhanger: not a precarious nor difficult dilemma nor shocking revelation... well, it was a shocking event earlier, but by the end, it's resolved: the boy is safe in the castle. Dictionary.com (By Oxford but not their main/official) says 'a melodramatic or adventure serial in which each installment ends in suspense in order to interest the reader or viewer in the next installment' and Merriam-Webster's Dictionary also says '1: an adventure serial or melodrama especially : one presented in installments each ending in suspense'. The ending isn't suspenseful either; what the main character (MC) talked about there is just normal. He may train like crazy, or train his daughter years in future, but that's not putting anyoe in imminent/immediate precarious danger because the ending is he's takes a nap, and beforehand decided to not do any of the extreme/dangerous things, though might train harder, but that's a normal thing done in relative safety (in contrast to adventuring).