Hope you're doing well! I hope this is a somewhat innocuous email that you might answer for me. Melisandre mentions that she expects Sam to show her (and Stannis, if I recall) the Black Gate under the Nightfort. There's no mention of Sam's having left Castle Black before taking ship to Braavos, so am I correct in assuming that he never returned to the Nightfort to show the gate to Melisandre?
I am sure she found it on her own.