Z for Zachariah
(2016)

John (Chiwetel Ejiofor) and Caleb (Chris Pine) are helping Ann (Margot Robbie) build a power generator by the waterfall, when Caleb slips off the ledge. John grabs hold of him, but the film abruptly cuts to John telling Ann that Caleb left after finishing the job. It's up to the viewer to decide if John killed Caleb, if Caleb died accidentally, or if John was telling the truth. 

Thanks Brad!

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