In situations like this the answer usually comes by flipping it and assuming they do understand, and asking why it makes sense now.

It's probably just the old 'fake loader' psychology, to be honest. Waiting without knowing when the elevator will arrive is boring/frustrating, where getting into an elevator that moves, even if the wrong direction, feels like progress.

Things are happening, and even if it takes longer ultimately that's a less frustrating state to be in.