The holodisk will unlock the hazmat pod in the hazmat testing ground.
The holotape can be found in Z-43 innovative toxins plant, on the first floor of the building, in the room directly ahead as you enter. Go straight to the back of the building on the first floor (you'll have a fight on your hands), then turn left into a smaller room. The holotape is behind a white box, leaning on the second filing cabinet in that same room.
Unlock Code: 646F6E7470616E6963
Behind the scenes
The hex code converts to 'dontpanic', a nod to Hitchhiker's Guide to the Galaxy.