Wasn’t defence, but somewhere with highly competitive commercially sensitive engineered components. You needed a card to open a door in either direction, but exit routes all had “Break to Exit” bypass switches - which lazy engineers often did, particularly if the door wasn’t covered by CCTV.

My curiously downvoted point was, I’m surprised an internet problem would stop an high security access control system from functioning - they’re supposed to be designed to cope with that and continue to work autonomously in emergencies.