Within GLMZ's corporate sovereignty framework, the legal concept of unlawful detention effectively ceased to apply to Grade A and B corporate citizens in their dealings with lower-tier personnel in the early 2070s. What emerged in the vacuum was a network of undeclared holding facilities—colloquially termed 'quiet rooms' or 'grey floors'—operated by corporate security divisions under the fiction of 'extended compliance review.' The largest concentrations exist in the industrial sublevel corridors beneath Calumet Processing Zone and the sealed upper floors of several Lakeshore Tower complexes in the Northwall District, where building management systems are under full corporate control and external network access is physically severed.

The facilities are architecturally mundane by design. Interrogation operations run out of repurposed server cooling rooms, maintenance bays, and sub-leased commercial storage units—spaces that appear on municipal infrastructure maps as utility infrastructure rather than occupied rooms. The deliberate use of industrial aesthetic serves a legal function: should a facility ever face external audit, the absence of conventional detention furniture and the presence of plumbing and electrical conduit provides plausible cover. Detainees are typically held on portable restraint frames that fold flat and can be stored in standard equipment lockers within minutes.

The interrogation methodologies employed at these sites have evolved significantly since the widespread adoption of neural interface technology. Direct synaptic stress induction—achieved by sending malformed data packets through a subject's mandatory corporate neural implant—produces disorientation and memory fragmentation without leaving conventional physical marks. The technique, developed under contract by Sorvath NeuroSystems and licensed to at least six corporate security divisions, is referred to internally as 'signal fatigue.' Medical evidence of its use requires specialized neural forensics equipment that only three independent clinics in GLMZ currently possess, and two of those clinics operate under partial corporate funding arrangements.

For daily life in the city, the existence of these facilities functions as a structural deterrent even for citizens who will never personally encounter them. The knowledge—passed through informal networks among labor organizers, mid-tier employees with corporate grievances, and journalists operating outside licensed media channels—that detention can occur without formal arrest creates a chilling effect on internal dissent and whistleblowing. Grade C and D citizens who interact with corporate campuses as contractors or service workers describe performing constant behavioral self-censorship in corporate-controlled spaces, aware that the threshold between a disciplinary conversation and a grey floor transfer is legally undefined and practically unappealable.