To see a special Thank You "Along with some awesome music" during the Quest "Seat Of The Quest being one the longest and difficult quests in the game you can get a Thank You from the creators of said quest. The get this do the following.

1. Get through Control Tower and arrive on the beach.

2. Talk to Elly. She will ask you to wait at the Pioneer 2 for Her.

At this point a Portal back will open up but do NOT go in. Instead follow her as she starts to walk away, she will go to a different portal that leads to Pioneer 2 but once again do NOT go in this one either. She will say "I just want to stay a little longer I'm so sad" or something along those lines. At which point a great in-game cutscene will take place showing your character and Elly watching the Ocean. Then a message will appear on the screen -Impossible to miss- and it will give a thanks from the developers and a Credit Roll for this Quest.

Note: This optional bonus does nothing for your character or storyline that i know of, but it is great to actually go through the whole quest.