Which of the following is an important design feature for the outer door o f a mantrap?

An alarmed emergency button that opens the outer door would create a social engineering vulnerability, allowing an attacker to trigger the alarm intentionally to bypass access controls.

While two-person integrity (TPI) policies exist in some high-security environments, it is not a defining design feature of the mantrap door mechanism itself and is not universally required.

CCTV monitoring of the mantrap is actually a recommended security best practice, not something to be avoided, as it provides accountability and evidence of who enters and exits the controlled space.

A core security principle of a mantrap (also called an airlock) is that the outer door and inner door must be interlocked so that only one door can be open at a time. This prevents tailgating and piggybacking by ensuring an individual is fully contained and verified in the vestibule before the inner door is released, and the outer door cannot be opened again until the inner door is secured.