Destroying the Flat Trans
Yep, there are two endings to this one—so hold on tight.
Mark's story ends in Asheville. Him, Trina, Alec, and Deedee barely make it in time to the Flat Trans going to Alaska. Mark urges Deedee to go through it alone, to safety. By doing this, Mark is pretty much giving the people in Alaska (who end up being WICKED) a fighting chance to find the cure to the Flare. After all, Deedee's immune.
But for Mark, Trina, and Alec, the end of the book is the end of their lives. Though we don't see them die, Alec is split-seconds away from crashing the Berg into the building by the time the last page ends.
Now, this might seem sad to y'all. But really, this is actually a happy ending… believe it or not. Remember, they all have the Flare. They're all going to die anyway. By crashing the Berg into the building, Alec is saving them all from going crazy and suffering.
Additionally, Alec crashing the Berg into that particular building is a great thing because it will destroy the Flat Trans, and by destroying the Flat Trans, the infected (like Bruce) won't be able to travel through it to attack the PFC. So in the end, they're protecting Deedee... and the world.
But most importantly, the very last line in the book is this: "Mark" (67.35). This is spoken by Trina, who, up until this point, seemed to have lost her memory of Mark. Hopefully, this line means that Mark can find peace in his last moments; Trina finally remembers him, and they can both die on their own terms in each other's arms.
Okay, so it's not really a happy ending. But hey, it could be much worse.
My Name is Deedee
Who saw it coming? Anyone? Anyone?
By this point, we hope you realize we're talking about the secret file of Teresa; the one where her memory is restored. Basically, this wraps up The Maze Runner series nicely and puts a shiny bow on top.
In this secret file, Teresa meets Thomas for the first time in WICKED. They bond for a little bit, and they definitely seem to like each other, so Thomas tells Teresa about his past—which we pretty much know about already. But then Thomas asks Teresa about her past, and that's when we get the mind-explosion moment.
In the last two lines, Teresa tells Thomas that her name before coming to WICKED was Deedee, and then she tells him the story. You know: the entire book we just read. The story about Mark and Alec and Trina and whatnot.
So yes, Deedee = Teresa. Teresa = Deedee. Insane revelation? Maybe. But what's it all mean?
Not to be Debbie Downers, but let's think about it. Mark and his friends are martyrs, and they save Teresa's life. And we know the rest of Teresa's life—she gets crushed by a boulder right before getting to paradise. Yeesh.
Ugh, Mark, his friends, and Teresa go through all of that just so Teresa can get crushed by a boulder? What a rip-off.
But let's not get too salty about things. At least Teresa is one of the main reasons the Gladers actually get to paradise. In the end, Teresa does exactly what Mark does—she sacrifices herself for the preservation of the human race. And there's really no better way to die than that.