Sudden flash; sudden downing of tools (9,6)
I believe the answer is:
lightning strike
'sudden' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'flash sudden downing of tools' is the wordplay.
I cannot quite understand how this works, but
'flash' could be 'lightning' (lightning is a kind of flash) and 'lightning' is found in the answer.
'downing of tools' could be 'strike' (I've seen this before) and 'strike' is present in the answer.
No letters remain.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for lightning strike that I've seen before include "Spontaneous coming out" , "Type of industrial action" , "that a place only witnesses once?" , "Rare event" , "not supposed to be repeated in one place" .)