Writing Prompt: Small Actions Lead to Big Disasters

Sometimes disasters begin with the smallest of actions.  On the ill-fated Apollo 13 mission, it began with a simple request from Mission Control:

...if you could give your Oxygen tanks a stir . . .

Damaged Apollo 13 Service Module after Separation (NASA / Public Domain Image)

That simple request and an electrical short set off an explosion that turned a mission to the moon into a life and death struggle for survival. The successful return of Apollo 13 is one of the most inspirational stories of space program heroism.  For today's writing prompt, write a story of a dangerous life and death event that starts with a -

small incident.