Scatter plot of the runaway stars, with the radial velocity and age colored by mass. Squares are group 1, diamonds are group 2, and dots are the rest of the runaways. These groups are the runaways selected by ejection direction only. The two groups are distinctly separate in both age and velocity. Group 2 contains two subgroups ejected in the same direction but at slightly different times. For the purpose of demonstrating the SCES mechanism, we focus on the later forming subgroup in group 2. The red rectangles indicate the additional filtering of the runaway groups by age and velocity.