; (II) 4 hours total during any 24-hour period; or (III) 12 hours total during any 7-day period; or (v) as part of a Federal agency-wide, Federal facility-wide, or partial Federal facility-wide lockdown, and— (I) only if a head of a Federal facility or Federal agency has determined the lockdown is necessary to de-escalate an emergency that involves several incarcerated persons and poses a specific and significant risk of imminent serious physical injury to the staff or incarcerated persons; (II) only when there are no less restrictive means to address an emergency, as a last resort after exhausting less restrictive measures; (III) if the lockdown is confined to as narrow an area as possible and to as limited number of people as possible; and (IV) if the lockdown is reviewed every hour by the head of the Federal facility or Federal agency, with notification provided to the Federal agency regional or field office, or equivalent office responsible for oversight of the Federal facility, beginning at the time the lockdown has lasted 2 hours, and is lifted as quickly as possible, provided that such lockdown shall not exceed— (aa) 4 hours total from the time at which the lockdown starts; (bb) 4 hours total during any 24-hour period