The problem with that segment is that Jeff picked one of the few missions in the game which are made for 12 people and don't allow NPCs, which is the reason why it was such a slog.
That said, even if you don't want to party up with other people, all you have to do is:
1. Choose a quest.
2. View all parties doing the quest (you can even show parties in other blocks now).
3. Choose the party which is in the most populated multiplayer area (11/12, 10/12, 9/12 etc.).
4. Choose to "Join as another party".
This way you reap all of the benefits of playing with people - monsters dying very fast, heals and revives while not actually having to talk with anyone.
While I was happy that PSO2 was featured on GB again, that particular quest and playing it alone didn't do the game justice.
After watching it I launched the game, got into a random party for an emergency quest and enjoyed 30 minutes of crazy explosions, punching hordes of monster in the face with my fists and around ~1 million xp.