Moment 0 (dashed black contour) and 1 (color scale) maps of the CH₃OH 218.440 GHz (a) and SiO 217.205 GHz (b). The 1.3 mm continuum emission is shown with the grey dashed contours of the same levels as in Fig. A.3. The contours for CH₃OH and SiO are 5, 15, 30, 90 times 1σ_rms of 11.70 mJy beam⁻¹ km s⁻¹ and 3, 7, 15, 30 times 1σ_rms of 15.49 mJy beam⁻¹ km s⁻¹, respectively. The maser cloudlets taken from Nguyen et al. (2022) are represented with circles whose sizes are proportional to the logarithm of brightness and colors scale to the velocity shown by the wedges. The cloudlets are grouped by colored, dashed boxes corresponding to the BS and RS emission, showing periodic anticorrelated variability, as defined in Sect. 3. The synthesized beam is shown in the bottom left for both images.