Hang on a minute! Has the FT community really just concluded that opening a door, or trying to, in mid-flight is safe?

Yes, the doors do open inwards to break the seal, but the big door handle does just that, and that's why it's so big - to give the leverage to break the seal. Pulling it will depressurise the cabin pretty quickly. Once the door moves inwards away from the seal it swings so that the door twists out of the doorway. Watch the way it moves sometime.