Flow of current through human body to the floor
I'm having trouble understanding the flow of current from a live wire
  to the floor via a human.


Some current is through conduction but also some current is due to capacitive coupling between body and earth. The human body has typically 100 pF capacitance to ground. Reliance on a conductive path does not mean current can't flow due to capacitance.


  In the same sense, how does current flow to the mud in the earth
  ground if the mud is non conducting in nature?


Mud conducts due to several reasons, not least that water can be made to conduct quite easily.