CCTV footage on a Shanghai train has captured the stunning and confounding moment a whole train carriage of commuters abandoned a seriously ill man.

The man, in a light green shirt, is sitting between commuters in a full carriage. He appears to be slightly disoriented before slumping onto the woman sitting next to him and falling to the floor.

But as surprising as his fainting episode was, what happened next was even more astonishing.

In the space of seconds, the carriage empties as passengers flee, leaving the man lying alone on the floor.

More bizarre still, the video also includes CCTV footage from each end of the station platform seconds later, as passengers flee the train onto the platform. Many of the commuters appear to have no idea why they’re running away, joining in the mob mentality.

Finally, the footage shows new passengers boarding the train and warily eyeing the man in the green shirt, who has been revived — no doubt by the stampede outside — and is looking confused.