Went public with shocks, essentially all at the same time (2,4)
I believe the answer is:
en bloc
'at the same time' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for en bloc that I've seen before include "As a whole (body)" , "Wholesale, as one unit" , "All at the same time - in France" , "in wholesale fashion" , "As a group (French)" .)