Brownian dynamics is used to describe the elimination of a particle aggregate through an absorbing pore. New dynamic effects are demonstrated by considering the distribution of velocity of the particles as well as position. In the transient state, as the system evolves toward the empty pore, the time dependent particle density is greater in the center of the pore than on the walls. The average dynamics of the particles is initially free diffusion with an early stage diffusion constant. Coupling between the position and the velocity of the particles sets up a flow field which contributes to the long time dynamics and leads to an increased value of effective long time diffusion constant. The transport of particles along the walls is enhanced, Particles are absorbed through the pore walls reducing the total flux at the exit of the pore. Based on these results, a possible separation mechanism for a gas mixture in a nanopore is discussed.