Se eu me lembro do filme corretamente, Caleb é pego de surpresa porque ele já começou a ter empatia com Ava, e ver Nathan desmontando ou descartando suas tentativas anteriores lhe parece como se Nathan estivesse fazendo isso para seres sencientes, tratando-os como se eles fossem eram máquinas. Então eu acho que os logs de vídeo fazem ele temer pelo futuro de Ava quando o experimento acabar.
Acho que o seguinte diálogo entre Nathan e Caleb mostra o estado de espírito deste último:
Caleb: "I didn't know there was gonna be a model after Ava."
Nathan: "Yeah, why? You thought she was a one-off?"
Caleb: "No, I knew there must have been prototypes. So I... I knew she wasn't the first, but I thought maybe the last."
Nathan: "Well, Ava doesn't exist in isolation any more than you or me. She's part of a continuum. So Version 9.6 and so on. And each time they get a little bit better."
Caleb: "When you make a new model, what do you do with the old one?"
Nathan: "Well, I, uh... download the mind, unpack the data. Add in the new routines I've been writing. And to do that you end up partially formatting, so the memories go. But the body survives. And Ava's body is a good one. You feel bad for Ava?"