That's it? Campbell's just going to kill himself? After everything he's been through, after everything we've watched him go through, after all those escapes, he's just going to off himself?
Why did we even read this whole thing if Campbell was just going to throw it all away?
Well, as in the carnage of war, the ends don't necessarily justify the means. In this case, Campbell's death isn't for us; it's for him. It may make zero sense. That's often the point in postmodern lit: nothing is anything, anyway, so why bother? We're not just looking for meaning in all the wrong places, but we're wrong for looking for meaning in the first place, because there isn't any.
Counterpoint: maybe there's some method to this madness. After all, the one thing we know about Campbell is that he hasn't been able to fully punish himself, even though he's technically some version of innocent. He's sort of giving himself the death penalty even if he's cleared of all charges. That makes sense, because as Vonnegut likes to point out, on some fundamental level, we are what we pretend to be. That makes Campbell a pretty nasty person, even if he was just pretending.
Plus, buying the farm is Campbell's way of completing the "story" he's been writing about himself:
I think that tonight is the night I will hang Howard W. Campbell, Jr., for crimes against himself. I know that tonight is the night. (45.55-56)
Earlier, Campbell mentioned that he should have killed himself when Helga died, because that's what a romantic hero in one of his plays would do. But he didn't know then that that was his cue. It's as if this is his second chance on stage, and he's taking his final curtain call the right way. As he sees it.
Hey, live by the pen, die by the pen, we guess.