Isso foi abordado pelo ator principal e diretor do filme em uma entrevista à revista Time. Em suma, o final foi intencionalmente deixado ambíguo, mas é razoavelmente claro (pelo menos para os diretores do filme) que Loomis realmente matou Caleb.
Did John drop Caleb?
Zobel: I think you know.
I think he does…
Zobel: Yeah. I feel like it’s heavily hinted at.
Definitely, but I did leave wondering if maybe he did decide, It’s too crazy, I’m just gonna hit the road.
Ejiofor: That’s not a terrible thing to think. I think it’s slated one way, heavier in one direction than the other.
Zobel: Sure. Because you don’t get that moment, you’re allowed to have hope.
Do you think Ann knows?
Ejiofor: She’s gotta be deeply suspicious either way. The real thing is what they can rebuild—and if they can. Or is there a point where she does drive him off the land. Is that in their future? Or is there a future in which they actually figure it out?
Zobel: It certainly isn’t superfluous why Caleb isn’t there anymore, but certainly the fact that he’s gone and Loomis is by himself is enough of the problem for her. I think it’s a different story if you fast-forward two days after the movie ended to, like, six months after the movie ended—might totally be different stories.
Chiwetel Ejiofor and Craig Zobel on Z for Zachariah‘s Surprising Ending