Can't put it down

This book is really out of my box too. I almost feel a little guilty that I can't stop reading. Why is something so disturbing and violent also so compelling? It's not 'my' world. I think what I find really interesting now is the way the violence has 'become' him. Between the migraines and the automatic behavior - it's uncanny. I'm not really sure where we're supposed to be in the book, but I'm at a place where Beah has completely become a soldier. He is now acting in the same way he found so appalling and animalistic - the behaviors he had first seen in the rebels toward his family.
How does this change occur? When, what, how is the switch finally flipped to the point that killing and destroying is now not only normal but enjoyable for him?