It appears that- at least once- this technique was successful and everything from then on was simply trying to replicate it.
This. This here. That's gotta be us.
Current theory: we're somebody else's soul jammed into the body of this "Alexander" fellow. Where's Alexander? I dunno-- but it seems his soul is possessing Piecewise from time to time.
We've got the information we wanted. It's time to get out of here.
I say we take some notes back. Specifically, the ones that pertain to us. Do not take notes for all the other projects, that breadth of missing info would point to a break in or theft.
You look through the notes one last time and select the ones you think are the most pertinent. You carefully fold them up and hide them away in you shirt before tidying up the room and putting everything back how you found it, or at least as close as you can remember. You close the door behind you and skedaddle back to the maintenance closet, careful to shut off any lights you've turned on along the way. You climb back up into the ceiling and then, with some difficulty, close the ladder and shove it so it lands, propped up against the wall like before. From there its nothing but two sections of vent work to refit and reattach before you climb back up and out of the vent.
Despite your best efforts to be as quiet as possible, when you exit the roof vent you can hear guards moving about. You immediately press yourself flat against the roof and lay utterly motionless, waiting and listening. You can tell from the bits of conversation you can pick up that they've heard noises from the building and are going to investigate. So far they don't seem to be alarmed, just cautious. They grumble about "Things in the lab" and "Break outs" and not being paid enough. You hear at least one of them open the door to this building, but there seem to be others milling about.
You listen hard. You try to place each individual guard's location via nothing but the sound of their footsteps and voice. There was at least one inside, two by the front door, and two more who seem to be walking the perimeter looking for something. You consider your options. You could just wait here for them to lose interest. Chances are they wouldn't check the roof; you don't see any access to it and there's a two foot tall lip running around the edge of the building that should prevent anyone from seeing you unless they're on or above the level of the roof. But waiting might take a while, and you may end up having to either risk daylight maneuvers or waiting till the next night. You could go when the guards checking the perimeter have walked past; it would be like how you planned to get out, just with a much tighter window of opportunity. You could cause a distraction...you still have the rats with you, could send one of them off to make noises elsewhere...or you could send one out into the open to give the guards a good explanation for the noises they heard. Of course that assumes none of them can see the threads connecting the rats to you; you remember Esme did mention there are tools that allow non-necromancers to see the anima, these guards may have access to them. Maybe.
You sneak a look at your watch.
Its 4:43. Its going to start getting brighter soon.