What is the difference between a nonretriggerable and retriggerable One Shot?
In a retriggerable MMV a new trigger during a pulse will restart the pulse time, and thus extend the current pulse.
If the pulse time is 10 s and you would retrigger 6 s after the first trigger you would get a 16 s pulse.  



In a non-retriggerable MMV the second trigger will be ignored and you'll get a 10 s pulse: