Channel maps of ¹³CO (2–1, top panels) and SO (5₆–4₅, bottom panels) emission in the interferometric data. The black contours are the 5, 10, and 15σ levels for the respective molecule, and the blue dotted contours are the corresponding negative values. The black + signs mark the position of the mm emission peaks of MMS1a and b. The blue and red arrows guide the eye to the direction of the respective Doppler-shifted emission. The shaded ellipse in the lower left corners indicate the synthesized beam of 0.44′′ × 0.36′′ (PA 61°) for both data cubes.