1. Spotting every guard patterns. There's a Goliath around but assuming the Tormentor in use is silenced indoors/outdoors, and no alarm is triggered, it won't bother you at all.
Also, there's often at least one NPC getting out and standing by forever because he has missions to offer. You have to take care of them because they can see you eliminating the patrols.
Now, let's start eliminating them, those on the roofs are first. You can let them start their analysis and pop the Torm, shot at this moment, Torm in the holster. They are caught the pants down, point-blank, no shields, hands busy with the analyser.
Then, let's proceed with the outside perimeters first, they are left alone in unfrequented corners. And so on, until the center of the facility. Here, you must watch for random civilians/guards going in and out from buildings that can come across the bodies, but you took a few minutes to look after that at first, so no surprises here.
You must take care that those bodies should be in dead corners. Here, two examples in building corners so no one can spot them from the windows, or even doors opening.
Sometimes as you are ending your eliminations, it may come harder to properly hide them, so if there is one or two last guards approaching dangerously your clues, just jump in front of them: he's going to scan you, kill him at this moment.
Now that the outside is quiet, you can proceed to the building themselves. At least one of the dead bodies out there has a level 1 access you can copy.
So here we are at the cafeteria: 3 civilians, so none of them is going to scan you. That's a tricky moment when you have to eliminate them all before they trigger the alarm, but they have no armour and handguns only. Keep them close, pop the Torm (take care there's a full mag on it!).
Congrats, now you have a level 2 access.
That may be enough for you to have the location of what/who you are looking for, or locate at least who's having the level 3, and so on.
I put the map marker thing so my next objective is shown on my hud, let's go to security side then.
to be continued...