8DAYS

Not really sure what the description means or what the reference is, but I unlocked this achievement on the second level (labs). There is a section where you are trying to avoid sensors and make it across a fairly large lab area. On the upper part of the area are several locker rooms. On the bottom half, there are computer rooms, with programmers.

I simply went from office to office and killed all the programmers (because why not?). When I killed the last one, the achievement unlocked.