Dynamics of a thin nematic liquid crystal sample in external switching field was examined for various initial states of electrostatic equilibrium. Step electric field was applied to study the gray scale switching dynamics from the first step equilibrium at $E_1$ to the second step equilibrium at $E_2$. We measured the switching times, and the results could be explained by a change in effective rotational viscosity and the Erickson-Leslie theory. We could divide the switching area into three regions of different characteristics, each respective range of which was dependent on surface anchoring. The switching time dependence on the second step field $(E_2)$ was determined by which region the first step field $(E_1)$ belongs to. Surface anchoring effects upon the gray scale dynamics are dominant to determine the switching times, and the switching time behaviors in the thin cell are found to have interesting analogies with those of confined liquid crystals. We also measured the switching behaviors of inertial effect and the switching behaviors of liquid crystal molecular near the surface of weak anchoring cell. We reported the possibilities of utilizing these effects for display devices.