PV diagrams perpendicular to the outflow axis of the H₂CO emission at the different heights indicated by vertical dashed lines in Fig. 3. Dotted white lines mark the position of the outflow axis (vertical) and the systemic velocity at 11.5 km s⁻¹ (horizontal). Dashed green lines in all panels trace the putative structures associated with the outflow cavity walls and shocked gas. The contour levels start at 2σ and are in steps of 2σ, 4σ, 6σ, and 8σ, where σ = 2.1 mJy beam⁻¹. The white bar represents the angular resolution ($0_{\cdot }^{\mathrm{\prime }\mathrm{\prime }}18$) and the channel width (0.5 km s⁻¹).