I'm not absolutely sure, but wasn't the sanctuary build and launched in some secret GTI base in what is GTVA terretory in the other universe?
If I have the backstory correctly in my head it was originally planed as a "superorion" and only rebuild into a sleepership after the fall of earth.
But if the Orion in orbit around Earth told command to start an evacuation would be nice I think. Even though most ships would be destroyed by the shivans, like it happened after the bombardment of Vasuda, only this time there is even less fighercover for the evacuationships.
I don't think there should be ANY dialogue about evacuation transports because it fundamentally alters the flow of the story.
Until you see those two patch-work fighters in the singularity system, you don't know that anyone is alive. And all evidence points to the contrary (ie the GTD Minnow). Having dialogue about people escaping tells you that there probably were survivors which would change the player's outlook and the mood of the story.
Dialogue can also quite frankly cheapen a situation.
Let the music carry the moment. The problem with many movies today is that people don't shut up. There's very few moments where there's a lot of silence. It's like Hollywood has ADD or something. But look at a movie like Conan, which has very little dialogue. Or look at the first Alien movie, where the mechanic is looking for his cat. Sometimes silence can be more powerful than words because the visual spectical conveys the emotion and the player can think up the dialogue for themselves.
I say leave the cutscene AS IS.