We wouldn't want to program emotion into a killing machine anyway. Emotions are messy, meatbag programs that make us do suboptimal things driven by our own cultural, societal and personal biases.

Trolley problem where one side is one person who is dear to you, other side is two people you don't know. The majority of people would save the person they know well even if two innocent but unknown people die.

Also we probably can't specifically program emotion until we understand it better, but I reckon we'll see emotions/similar concepts arise as we build more intelligent machines. Humans are not special, we're just meat computers.