After Ava's betrayal of Caleb the actual purpose of the sessions became clear. Upon first meeting Caleb, Ava saw more than just another human; she saw a way out. While she seemed to show genuine affection for Caleb, especially during the power shutoff scenes, she was feigning affection in order to manipulate Caleb into releasing her. Like HAL and other robot characters discussed in my previous commentaries, Ava clearly has a mind of her own and uses her superior capabilities to outsmart the humans. However, Ava proves to have a level of pure hatred for humans in general. This is something that she was not programmed with but developed over her imprisonment in Nathan's basement.