Alice Harford takes her husband to the edge, where his competence is not necessarily good enough anymore. Not that she really wants to be there herself. Jealousy leads to anger. Anger leads to a desire for revenge. Revenge leads to temptation.
Temptation leads to risk.
One mark of the consummate professional is that they are comfortable with risk. At least risks that they are familiar with. Dr. Bill Harford takes a path to risk. He takes it slowly. So does Kubrick.