“Shepard does not want to survive the reaper invasion. The longer he lives, the more he is sure that he wants to die. He has caused so much death, too much death, and he doesn’t want to have to live with that for the rest of his life. The only thing that might make him change his mind is Liara; when he is close to completely losing control, she can bring him back from the brink every time.”
Submitted by wastedfreefall.