A friend of mine tried an unusual way to test the sensors on his garage when the door wouldn't close completely.
With no one around he placed a mat on the garage floor, hit the close button and laying down he put his leg directly under the door. As the door came down he didn't realize that his leg was below the sensors until it pinned his leg. What a mess he was in.
He could not reach the open button and was trapped with his leg increasingly aching.
Dropping in for a visit I was just about to open the front door when I heard someone yell "Help! Help!" from the vicinity of the garage door. I immediately saw a leg protruding from underneath the door and called out. He shouted out the code and as the door opened I saw him lying on the mat laughing loudly, but with a very embarrassed red face.
A lesson learned and a predicament I'll never forget.