Why a door's "failure mode" is a real design decision, not an accident — and why the same building routinely uses both.
Every electronically controlled door has to answer one question that has nothing to do with normal operation: what should it do when power, the network link, or the access control panel itself is lost? There are exactly two possible defaults, and picking between them is a deliberate tradeoff between two things that are both, in the abstract, "security" — keeping people safe, and keeping an area protected. Which one wins during a failure isn't a matter of opinion. On many doors, it's dictated by fire and building code. On others, it's a conscious risk decision made by whoever designed the access control system.