Response to what the soldiers did? (8)
I believe the answer is:
reaction
'response' is the definition.
(synonyms)
'soldiers did?' is the wordplay.
'soldiers' becomes 're' (Royal Engineers).
'did?' becomes 'action' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
're'+'action'='REACTION'
'to what the' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for reaction that I've seen before include "Side-effect from drug" , "effect of drugs?" , "Chemical change or backlash" , "Into care (anag)" , "Creation found in response to event" .)