While making your way through the large office building, look for papers hung on the wall or scattered on desks. Many of these papers have "TPS Report" written on them, as well as a symbol including three boxes at the top. This is a reference to the popular movie Office Space in which the characters are involved with TPS reports at their office, Initech, which has almost the same logo as the symbol at the top of the papers.
While making your way through the large office building, about midway through the level there should be a large room filled with cubicles, with multiple offices on the side. One of the cubicles in the middle of the room has a lot of boxes piled into it, with a red stapler on the desk. This is in reference to the character Milton in Office Space. Management is always making Milton move his desk and using his area for storage, as well as stealing his red Swingline stapler. This can be found in the same area as the multiple TPS reports.