Hey. So this was actually the first daily mission i did and on challenging. needless to say i was blown away at the difficulty scaling. In the end i really enjoyed it though, it more than forced a lot of tactical rethinking. I beat this with a full squad in 1hr54min. The part on the rooftop where you first get out of the elevator is brutal, no doubt. What my team and i did was have 1 agent geared towards marksman focus on popping out near the first brick column to finish off low health enemies. In the first moments of this section though thats near impossible due to the influx of charging enemies. We all equipped/spammed seeker mines and took turns popping out and laying down fire to eventually push back the front line until we could start moving out and begin the "picking off" process i mentioned earlier. At least 15 mins of the rooftop section was spent in that first room adjacent to the elevator. Truly a test of patience lol. Dont fret though, because after that when you progress to the boss encounter, you'll wish you were back on the rooftop XD For that section have 2 agents stationed dead center 1 on floor 1 and 1 on floor 2, respectively, preferably marksman, as the other 2 agents alternate left and right side wings to hold off the enemies from making an attempt at rushing the stair wells and pinning you down in the mid-back room. Incindiary bullets/turrets with wildfire talent to boost chance of applying burn damage for AOE helps too. Im sure many other people have different strategies that worked better for them but this is how we did it. Good luck, you can do it!