Moral Event Horizon: Weir is The Woobie dealing with Jerk Ass crewmates - but then he deliberately crosses the Moral Event Horizon by refusing to let the others leave because he has nothing to live for anymore.
Weir: You can't leave. She won't let you.
Miller: You just get your gear and get back on the Lewis & Clark, Doctor, or you'll find yourself walkin' home.
Weir: I am home.