The first sentence in the example contains a comma splice (two sentences incorrectly joined by a comma).
The second actual sentence (beginning with As you know) needs a comma after know.
Welcome to Eden Station. As you know, the Earth is about to be destroyed. Please follow the green line to your assigned quarters and enjoy the show.
I don’t like the second sentence — it’s quite clunky — but I don’t see any easy way to fix it, and I don’t feel like rewriting the whole thing for a mere grammar-and-punctuation exercise.