Overview of three less evolved regions of our sample: G28IRS2, G28P1, and G28S. In this case, all of them belong to the same IRDC G28. Left: Spitzer (8 μm) view of the whole IRDC G28. The three target sub-regions are depicted with millimetre contours (white) from ALMA for G28IRS2 (Molinari et al. 2025) and G28P1 (Zhang et al. 2015), and from SMA for G28S (Feng et al. 2016a), with cyan boxes highlighting the field of view of our MIRI observations, which are slightly magnified for better visualisation. Middle and right panels: Zoomed-in views of the target sub-regions. These show the MIRI continuum at 14 μm, whereas cyan contours trace the continuum at 5 μm (no IR source was detected towards G28S). The ellipses in the bottom right corners represent beam sizes: grey for the 14 μm image and cyan for the 5 μm contours.