What happens to those left in the maze in "The Maze Runner"?

Question

At the end of the movie The Maze Runner:

A group is able to escape the maze, led by Thomas. Whilst Gally and a group of his friends stay in the maze. However Gally also finds his way out of the maze after Thomas. Although we never see his group of friends escape the maze.

So what happens to those left in the maze?

Answer 1

We never find the answer. Even in the book Trilogy, a lot of the questions that are raised are never answered although it does have a satisfying conclusion.