The Fridge is one of SHIELD’s most secure facilities, housing dangerous artefacts and prisoners that cannot be kept securely at other locations. Some if the items supposedly destroyed at the Slingshot were in facts transported to the Fridge for storage and study. Access to the building was restricted, with personnel only able to enter via a secure checkpoint on the top level.
The facility was initially one of the few facilities to remain secure after the HYDRA breach until Ward, whose cover was still intact breached the facility. HYDRA raided the building, securing weapons and freeing prisoners to keep SHIELD occupied.