Usually there are muster stations where a designated emergency captain takes attendance for everyone who is expected to be present and a remote operations cente

Usually there are muster stations where a designated emergency captain takes attendance for everyone who is expected to be present and a remote operations center that has access to HRIS data to know who is out/on vacation when that attendance is known. Door locks during an emergency are usually denoted to be fail-open so someone doesn't get trapped, though that may differ depending on the security level of the facility.