Redshift evolution of the cosine of the angle between the radial direction towards the pair (center of mass, blue; GC1, red) and the velocity of the subhalo (bulk, solid; bound gas, dashed; all gas within R₅₀₀, dotted). The gas velocity alignment is reported only for the infall direction towards GC1. Data points for all the gas within R₅₀₀ are only defined for the redshifts when the clump is an independent group from GC1 (z ≳ 0.16). We also report the redshift evolution of the subhalo DM (solid lines) and gas (dashed lines) bound mass in the lower inset of the figure.