Comparison between the velocity centroids, v_c, and line widths, Δv, of the [CII] and CRRL line profiles. v_c and Δv are determined from a multicomponent Gaussian fit to the observed spectra (Fig. 2). The top panel shows the velocity centroids, the upper middle panel shows the difference between the closest velocity centroids in units of its error, Z score, the lower middle panel shows the standard deviation of the Gaussian line profile, and the lower panel shows the ratio Δv([CII])∕Δv([CRRL]). The starred symbols show the [CII] components that are closest in velocity to the CRRLs.