@rslade wrote:
... the primary phys sec concept: life safety. ... for example, escape a fire ...
Life-safety encompasses more than just fire-safety. I was reminded of this today when I got an alert that my kids's school was on lock-down due to an external threat (subsequently resolved without injury). The best failure state for a (non-public) office door is to prevent ingress while permitting egress (e.g. locked only from the outside).
Since the question refers to "secure entry system", the best answer is (B) fail-closed because it is specifically asking about ingress, which implies that egress occurs through different doors.
Had the question been "For an office building, the doors should be set at:", the best answer would be (A) fail-open because when balancing both the ingress and egress scenarios one must take into account that failures are more likely to occur because of a fire than during an attack.
On the other hand, if this question were to come up on a CISSP exam, I probably would select "A" because the test-taking objective is to select the same answer as the author; not to select the answer you can best (pedantically) defend.
That said, "fail-open", "fail-closed" and "fail-locked" are not the best terms to use when referring to a door because "open" can mean either "ajar" or "unlocked" and because it is possible for a door to be simultaneously locked from the outside yet latched from the inside. Much clearer is to use "locked only from the outside" or "dead-bolted". In more technical settings the words ingress and egress are also useful for absolute clarity.
I presume that @Chuxing's original comment was that his building was preventing egress. If management does not get that corrected, it should be reported to the local fire chief.
