SMA high-velocity ¹²CO bullets overlaid with the JVLA methanol maser emission (Menten, priv. comm.). The red and blue ¹²CO emission contours are the same as shown in Figs. 1 and 3. The CH₃OH 4_2,2 − 4_1,3 E maser emission is shown in gray contours plotted 0.05 to 3.05 Jy beam^-1 in step of 0.2 Jy beam^-1. The black dashed line indicates the possible symmetric distribution between the ¹²CO and CH₃OH emission, where most of the high-velocity ¹²CO bullets are likely absorbed below this line. The positions of the explosion center (EC), source BN, HC, and H₂ peak 1 and 2 are marked. Magenta triangles represent the positions of source I, SMA-1, source n, and IRc7 (east to west). The three strongest methyl formate emission peaks are marked in black stars (Favre et al. 2011).