Stuck in Sycarus Tower

On the set of mobs between the 2nd and 3rd bosses of Sycarus Tower; after clearing out all the mobs, the Red Dragon did not land. At the time, I had been slow to follow the party, so they pulled the boss when I was on the previous floor, and I was not able to make it past the line by the time the area locked.

Logging out did not fix the issue, and neither myself (outside the area) nor any of the players within the fight area could vote abandon or vote dismiss, due to some of the members being listed as "In Battle".

Eventually managed to escape by coordinating everybody logging out simultaneously, and quickly leaving dungeon when they logged back in!