The Maze Runner question

"The Maze Runner" is an adventurous and suspenseful book by James Dashner. The main character Thomas wakes up in an elevator that takes him into a place filled with only boys called "the Glade". Thomas has no memory of how he got there or who he is. The only memory kept was his name. He then finds out the two leaders of the Glade, Alby and Newt, have made basic, but effective rules that keep them working as a team. The elevator box that brought Thomas there is brought up every week with food and new tools. Every month a new boy finds himself inside the elevator box with nohting but his name. The Glade is enclosed by squarely four mile-high walls made of concrete. Outside the walls of the Glade is the Maze, a puzzle filled with ivy that changes everyday. The Maze is filled with "Grievers", a shapeless creature half metal and flesh. The Gladers have been trying to solve the Maze by running through it and tracking the motions of the walls looking for an exit. The next day the elevator brings up a girl whose name is Teresa with a note that read "She's the last one ever". This told the Gladers that there will no longer be anymore boys or girls sent. Teresa then falls into an unexpected coma after being sent to the Glade. Thomas then recognizes her after a visit to see what happened. She reveals that they knew each other before they were sent to the Glade and have an ability that allows them to talk telepathically. After Teresa's arrival things became different in the Glade: The sun seems to have gone, Gladers start to act differently, and the entrance to the Maze stays open which allows Grievers to pick on the Gladers. Thomas then figures out that the Maze isn't moving randomly, but rather a code that spells out words. He also learns that the cliff that looked like nothing but a cliff turned out to be a Griever hole a place where Grievers leave the Maze. They come up with a plan to enter the hole to forever leave the Maze. Most of the Gladers follow the plan knowing they might die knowing that they will be face-to-face with a Griever, but nothing is worse than staying in the Glade waiting for the Grievers to come to you. They succeed completing the Maze, but are then surprised by Gally, a boy who knew Thomas was different from the Gladers which was the reason he hated him. He throws a knife at Thomas but fails because Chuck, the youngest of the Glade, jumps and takes the knife to the heart. Seconds after Chuck's death, twenty of the Gladers are rescued by a group of people and brought to a safe sanctuary.