I think that Ardbert's help made it easier for us to control the massive amount of light that had previously been killing us, and we used it -via the white auracite and the 'ghostly' bravura - to do what we had to. I think Emet saw us as an Ancient briefly because the rejoining with Ardbert brought us closer to that complete 'soul'. Whether we are actually that individual I would question though, although merging with Ardbert didn't seem to diminish us. It's an interesting point. It didn't seem like we lost Ardbert either since we saw through his eyes the reunion with his friends. Which is all very intriguing and means that perhaps rejoining isn't as desperately horrendous as we think?