A friend & I have been running through the last 15-20 missions together and we have encountered a few that do not let us progress if we are in the instance together. Fort Trinity is one and this is another.
I took the Rescue the Patrol fork and my friend took the Navy option. We’d finish my bit, but ran into some issues with his, so continued in my story while we tried to figure out a work-around. When we entered the Romke story instance, all the NPCs were there, including Trehearne, but the dialogue didn’t trigger.
We restarted with the same results. The third time, my friend didn’t enter the instance (although he was still in the party) and everything worked out okay.
For us, this wasn’t a big deal — we could continue the story fine and the mission was less fun to solo. However, I imagine it is dispiriting to some people to get this far and then have this sort of trouble.
Perhaps the game could check in advance if someone in the party was in a parallel story-line that might need to be completed first and offer a warning. (e.g. “one of your party members is involved in a parallel storyline — please consider finishing ___’s story or continuing with another combination of characters.”) Although this doesn’t resolve the root issue, it does make it easier for player to move forward without having to do their own troubleshooting.
John Smith: “you should kill monsters, because killing monsters is awesome.”