Lol Rotty, thats insane!
Take off was mad...
Thank you all for the kind responses!
A.
Surprised the CFI didn't point that out to you... next time you fly in that plane, check it out.
But don't pull the handle, or you'll owe them two new doors!!!

Actually, it's been a while, so I checked for a picture: there's one D-ring on each side, hanging near the door. It's pretty simple: there's a cable that passes through both hinge pins, and when you pull the handle, they come right out of both upper and lower hinge at the same time. Buh-bye, door! Then, with a parachute I hope, you bail out, unimpeded by a flapping door. Typical reason to have to do this would be control lock during extreme maneuvers... gotta know the airplane's limitations, but it's wise to be prepared, too.