My norn Ranger is part of the Vigil, and while doing the last episode of the Level 50 Personal Story Mission, the Vigil’s storyline got mixed up with the Durmand’s. Sieran appeared out of nowhere and started to talk, only to Forgal to speak only a few seconds later. It was funny to watch.. and it seems like Sieran had more dialogue than the norn mentor.
You can see a few screenshots here: http://imgur.com/a/iUGuZ