He nods again. "Thanks."
And into the neighbour's place he goes, and—
Logically speaking there isn't anything wrong with what he did. He responded reasonably to the situation at hand. If he lets strangers with pipes kill him, or beat him up and take his stuff, or whatever else they planned, then he will not succeed in finding Olaf. And also he will be dead, or beaten up and deprived of his stuff, or whatever else. He used an appropriate amount of force given the constraints he was working under.
But the logical approach has no room in it for the way he felt when the pipe connected with the girl's skull. He is fairly sure that there is something very wrong with that feeling. Normal people do not feel like that about killing someone. If they did, there would be a lot more murder in the world. The sort of person who feels like that about killing someone probably does a lot of murder.
If he did everything right, though, what does it matter if he felt much too good about it?
But if he felt that good about it, how does he know he isn't just making excuses? How does he know he won't kill more people, when it's convenient or he can get away with it, and tell himself it was the reasonable thing to do?
Also, he begins to suspect that along with the twenty-five kilos of insects he is supposed to be acquiring implicit proof that he knows how to deal with desperate strangers wielding pipes, and he doesn't quite know how he feels about that but he is pretty sure he doesn't like it. If Kukul realized he didn't know about the people with pipes, Kukul could have warned him.
It occurs to him, in unexpectedly vivid terms, that he could kill Kukul. He decides that that is not a reasonable response to the situation at hand. And also there would be some serious practical obstacles to getting away with it. And also it would probably upset that Karakul girl, who seemed nice. Oh, and murder is wrong, or something.
He takes an unusually long time getting to sleep.
In the morning, he cleans the dead person's clothes as best he can and exchanges money for insects and repacks his bag around the new load and makes sure that the gun is accessible but not visible and heads north to Lintu.