The Armory
The armory is a connected building to the warehouse. It is a large one room shed-like structure completely full of weapons of mass destruction. Ready for any heisting needs and non heisting needs, alike.
The walls are reinforced to deter from being broken into and the door has a security system specific to this one part of the building, separate from the warehouse's standard security.
Grey works out of the armory when he has to create devices and explosives for a job.