Strict at all times in case of sabotage (6)
I believe the answer is:
severe
'strict' is the definition.
(I've seen this before)
'at all times in case of sabotage' is the wordplay.
'at all times' becomes 'ever' (synonyms).
'in' means one lot of letters goes inside another.
'case of' says to hollow out the word (remove centre letters) (outsides of).
'sabotage' with its middle removed is 'se'.
'ever' going inside 'se' is 'SEVERE'.
(Other definitions for severe that I've seen before include "Terrible" , "Very plain in style or appearance" , "Harsh and exacting" , "Harsh; very plain" , "Harsh, rigorous" .)