Amir is a key character in this book because he shows many ways of how he tried to escape from his dreadful sins not only by confronting them.Discuss
The first way that Amir tries to really get away from his sins, particularly the most important one of ignoring Hassan's situation when Assef rapes him, is to figure out a way to have Baba get rid of Hassan and Ali. He tries to convince him to send them away but in the end has to make it look like Hassan stole from him.
When that doesn't really work, he eventually escapes to America, though there are other circumstances involved, it certainly helps him to have that kind of distance from the whole situation.
Of course both of these escapes fail and he has to confront them when Rahim Kahn calls to let him know "there is a way to be good again" and he returns to Afghanistan to confront his sins.