Unlocked double doors create their own hazard. There is the tendency to bust through them saloon style, partly out of hedging your bet for which one is unlocked, only to lay a Loony Tunes like booby trap for anyone following behind you:
In fairness though, most double doors aren't spring loaded like those idiotic saloon doors are so wouldn't hit people in the face in quite such violent fashion.
https://imgur.com/gallery/20YvUX1