A 73-year-old man was critically injured at a Tim Hortons drive-thru in Wallaceburg, Ont., after his head was pinned between his car door and a post.

Chatham-Kent police said the man drove up to the drive-thru on Tuesday around 1 p.m. in Wallaceburg, a community of about 11,000 between Sarnia and Chatham.

Police said the man dropped something, then tried to pick it up by reversing his vehicle, opening the driver's side door and leaning to the ground.

But while he was reaching out of the vehicle it reversed, pinning his head and neck between the door and a yellow post near the drive-thru window.

Other people in the drive-thru line jumped out of their cars and turned off the man's vehicle, but they weren't able to free him.

Police say when emergency crews arrived it appeared as though the man, from nearby Tupperville, Ont., was dead, but hospital staff revived him.

The man was flown from hospital in Chatham-Kent to a hospital in London.

Police said the man remained in critical condition early Wednesday.