I quite like this.  It's interesting to realize what would make your Maedhros, who is usually a pretty steady fellow, turn tail and flee.

This was just perfect and it makes so much sense. Maedhros was oath-bound to take some action, knowing where the Silmaril was. Luthien, with all her powers might as well have her own version of a girdle (it was so funny - ‘It seems I have found Luthien’s front gate’). I love how you work her known powers over sleep into something that reminds me of Irish tales. Maedhros's response is 

Great tale!