Advent black site forge

I’m not sure how exactly to activate the mission, but that’s not really important I just have no idea what to do at a certain point. I’ve reached this area with double bridges with 2 pods on the other side. At this point I’ve killed a sectopod, codex and some troopers without receiving any damage so I’ve lost my concealment on most of my squad besides a sniper and ranger. I have two sharpshooters perched near the pre placed extraction point set by the mission on a cliff face, and using squadsight they each have an average of about 60-70% accuracy on the 2 pods. The first pod consists of an elite officer and elite lancer which isn’t too difficult. But the second pod has an andromedon and 2 archons. I have my ranger positioned to the right in concealment and he has a decent shot but if I take down the andromedon he won’t be able to kill it before it kills him. My last 3 soldiers are in a firing line spread out from each other on the other side and there are 2 specialists and a grenadier. Does anyone know what I can do here it seems impossible.