I considered "The sun is dead!" as a battle cry for the terrorist when they try to bring down the solar energy company. It's metaphorical at best.

I agree with all of your concerns, and the game would need to be playtested to know for sure. It would be fun to play ten games and see how many end with the psychologist describing the epilogue and how many with the terrorist. Also, if you play the game again with the same group, perhaps they will go for the other ending. I don't know!

My idea was that the terrorist has to convince the other players that the outcome for their characters will be better in the terrorist's epilogue: perhaps they blow up the station and become space-pirates, which is cooler that the psychologist describing how everything goes back to normal and you're still stuck in your corporate job manning this space station.

Seating order makes a difference, and is also something I would like to playtest. If the terrorist is next to the psychologist, the psychologist can say no to all killings, but there's still the option for the terrorist to just play it cool and try to remain hidden and wait it out. If they can get the psychologist to point to someone else, the terrorist wins, so it becomes more about subterfuge than outright killings.

One of my favorite board games is the Battlestar Galactica game with hidden cylons among the players. I've also enjoyed playing the Werewolf/Mafia game where you switch between day and nighttime, and someone is working against the group and the rest have to find them. The "twist" in this game is that the neutral players get to decide who to side with, so it's not only about finding the terrorist. 

Thank you! I borrowed the Yes-And part from improv theater, but decided to base it on seating order. I don't know if it works! But it seems like it would be fun to leave the resolution of your actions to your fellow players and see what happens.