"With unexpected speed, he reared back and threw the knife at Thomas. As he did so, Thomas heard a shout to his right, sensed movement. Toward him. […] Then, inexplicably, Chuck was there, diving in front of him. Thomas felt as if his feet had been frozen in block of ice; he could only stare at the scene of horror unfolding before him, completely helpless. -James Dashner, The Maze Runner
Sacrifice is a righteous and monumental action to commit. A person will sacrifice themselves for the benefit of others for the sake of love and friendship. Jack and Rose have spent so much time together developing a budding romance. But when disaster strikes, there time together starts to come to an end. Both of them barely make it out, but that doesn't mean all is well. Jack sacrifices himself and lets the ocean swallow him to let Rose safely float away.
Gally swiftly and unexpectedly throws a knife at Thomas. Thomas has little to no time to react, but Thomas can't even move an inch as he is in shock. Chuck makes the noble and heroic sacrifice to jump in front of the knife. It impales him and causes him to bleed to death. Thomas describes what happened as a “Scene of horror unfolding before him, completely helpless”. Thomas had developed a great relationship with him. Not a romantic one like Rose and Jack, and not even a friendship considering all the times Chuck had irritated him. It was a father-son relationship. As chuck was quite younger than Thomas, thomas took it upon himself to watch out for chuck in a dangerous world where Chuck didn't even know who or where his parents were. Chuck cared about Thomas because of the role of a father figure Thomas took on. In reality, you don't see relationships like Thomas and Chuck or even Jack and Rose. Sacrifices are made, but not usually as great as the sacrifices by both Jack and Chuck.