Aurene is supposed to spawn and blast the wall down in the beginning but is not spawning. After the intro dialogue Rytlock, Zafirah and Caithe just stand there forever.
Here is a video of the bug: https://www.reddit.com/r/Guildwars2/comments/bp5xc7/descent_bugged_please_help_mespoilers/
This worked for me, if you are also stuck on this step try getting someone else to run you through their instance. This worked for me and now I have completed the story.
After testing with others you need to find someone who was not bugged, if a bugged person goes in Aurene will not spawn.
Aurene can still bug and not spawn but this does seem to be a workaround.
Jadis Narnia, Sylvari Ranger of [VoS]