This is the second version of the mod. And this time not 1, but there are 3 floors at once, these are: office, laboratory, zone with zombies, zone with test subjects (so far empty), zombies have appeared. Here is the video:
There is really one pattern. Notice while playing. Yes, and you probably noticed that at the beginning there were no zombies on the street, these are the ones that you did not kill on another floor (there are 2 floors with zombies), that is, they jump out of the windows.