PV diagram of the H₂CO emission along the outflow axis. This orientation of the axis was estimated by joining the peak of the MM2(E) continuum emission and the position of the MC source. Dotted lines mark the position of the source (vertical) and the velocity of the system, V_sys ≃ 11.5 km s⁻¹ (horizontal). Vertical dashed lines indicate the position where the perpendicular PV diagrams are made (see Fig. 4). 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).