A self realized person reaches state of self realization after negating karma to zero. In the circumstances how can karma affect a self realized soul? Probably we understood the meaning of karma wrongly. Karma cannot be equated to physical action alone.
A self realized soul even before reaching state of self realization indulged in karma nishkama karma way of life. By this we mean indulging in karma in a way that it does not produce any attachment whatsoever. Working with an unattached attitude is what nishkama, all about.
Negation of karma to zero means a self realized person as a soul atman has reached state of absolute purity 100%. Once dross impurities within negated to zero, there was no system or way it could be reimposed in the system.
Furthermore whenever a self realized person indulged in physical action, it was always for benefit of mankind. Such physical karma indulged for benefit of mankind does not produce any karmic attachment. Even if a self realized person commits a murder, it would not be called a murder.
A self realized person would not indulge in mother knowingly but if one does it would be for benefit of mankind. If a self realized person comes across bad person intent on outraging the modesty of a Lady then if a murder is committed, it would not be called a murder as per Bhagavad Gita.
Self realized souls are godly people like Mahavira, Gautama Buddha even Jesus Christ and Prophet Mohammed. Sri Ramakrishna Paramhansa and Maharshi Ramana also fall in this category. After reaching state of self realization, karma indulged by Mahavira, Gautama Buddha even Jesus Christ and Prophet Mohammed cannot be termed karma, it is nishkama karma yoga.