I believe that I have no right to take away the liberty or life of another unless they severely threaten my own life or liberty. I choose to live by this belief. It is not based on utility, but is partly based on that 'disgust' you mention. However, the choice itself, and the will behind it, do not come from disgust or pleasure.

Explain it to me via your model please.

Aside - your chemical pleasure model does not adequately explain the existence of a strong will, or choices based on will.