Over 2 years spent in the maze, the Gladers learn to bond and get to know one another. So they make friends and friendship is one of the things you notice throughout the novel. For a lot of the Gladers, they would risk their lives for another Glader, just like Alby. Alby sacrificed himself for everyone else. It showed that he was bonded with everyone and had great friends. Chuck and Thomas become great friends quickly, Alby and Newt seem to have quite a bit in common, Minho and Thomas fight till the end together and those are all tiny acts of friendship that happen often that becomes a theme in this novel, the maze runner.