Throughout Triage, guilt is constantly intertwined with the core of the novel. It affects Mark, Joaquin and Elena quite adversely and causes relationships to break down and change. The reader learns most about Mark's experience of "trauma" and being a "survivor" during the book. It is showcased how the guilt that he feels affects his relationship with Elena and how it eats away at him. Elena's guilt intertwines her with Joaquin. As Triage progresses, the guilt that she feels towards Joaquin and their relationship develops. Finally, Joaquin's guilt is akin in some ways to that of Marks. Within the book guilt is a main theme and is constantly concentrated on and referred to.
This guilt that is constantly focused on, is reflected in Mark's character quite regularly. The reader is shown, as Mark cuts himself off from the world, that the guilt that he cannot rid himself of immobilizes him. He numbs himself, the pain too much even if it is "preferable to numbness". He cannot react to situations and becomes but a mere shell of whom he had previously been. This factors into his relationship with Elena breaking down. He cannot communicate with her, his guilt only allowing the information or burden he carries to exist within the deepest reaches of his mind. The guilt not only grips him in its hold, it causes him to become sick and break down his relationships around him.
Elena on the other hand deals with a guilt that does not cause her to damage her interactions. Rather it boosts her to repair long forgotten family members (Joaquin). Before the guilt, when there is only anger and resent, her vision is shrouded, unable to see clearly. Once Elena's guilt does come to the for, it helps to clear her vision, causing her to realize how she had pushed aside Joaquin, "triage[d]" him as not an important factor in her life. This realization helps to maximize the guilt she feels and the uncertainty at what she should about her grandfather.