ALMA 2019 data. Each panel presents the combined PV plots, along the cut at PA = 133°, of the H30α emission (white contours; same as Fig. 3, lower panel) and a selected molecular line (color map): CH₃CN J_K = 12₃–11₃ (a); CH₃CN J_K = 12₆ –11₆ (b); ¹³CH₃CN J_K = 13₃–12₃ (c); and CH₃CN v₈ = 1 J_K,l = 12_2,1–11_2,1 (d). Panels b and d: emission of other transitions close in frequency to the selected line. In each panel, the vertical and horizontal white axes denote the positional offset (≈ −0.′′68) and V_LSR (≈112 km s⁻¹) of the YSO, respectively. The magenta curve shows the Keplerian velocity profile for a central mass of 20 M_⊙. In the lower left corner, the vertical and horizontal white error bars indicate the velocity and spatial resolutions, respectively.