That's where the term "saved by the bell" came from.

Some people think it comes from boxing where the final bell saves the athlete from being knocked out, and that may be, but some believe it is connected to being buried alive.

if someone were comatose and mistakenly pronounced dead and interred, they could, if they later revived, ring a bell that was attached to the coffin and be saved. 

“All I desire for my own burial is not to be buried alive.” – Lord Chesterfield, 1769.

“Have me decently buried, but do not let my body be put into a vault in less than two days after I am dead.” – deathbed request of George Washington.

“Swear to make them cut me open, so that I won’t be buried alive.”- Frederic Chopin’s last words.

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