I've heard that people can sometimes get out of dungeons like that if they log off and exit the game for a while (gives the game time to reset and your character will reappear outside the dungeon when you log back in). I don't know how long you should stay out of the game for this to work, though. Have you tried this?
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Kaylee Krankenwagen, level 60 GF | Tavandruil Wayfinder, level 49 GWF | Aldith Langley, level 51 HR
If you have no other option, this will work.