Top: SiO emission profile of the central channel, extracted from east to west through the center. The intensity axis has units of Jy beam⁻¹. The eastern (left) profile is overplotted as a grey dashed line over the western (right) profiles to highlight the asymmetry. The SiO void is highlighted by the green tag. The purple tags indicate the locations of the equidistant bumps in the inner portion of the SiO profile. Bottom: eastern profile in log-scale. The overplotted red dotted line exhibits a shift in regime between a slope of −0.77 for the inner 1.8″, and −2.6 for the outer part.