Company in rush to cause suffering (7)
I believe the answer is:
scourge
'cause suffering' is the definition.
(scourge can mean torment or afflict)
'company in rush' is the wordplay.
'company' becomes 'co' (abbreviation).
'in' means one lot of letters goes inside another.
'rush' becomes 'surge' (synonyms).
'co' put inside 'surge' is 'SCOURGE'.
'to' acts as a link.
(Other definitions for scourge that I've seen before include "administer punishment" , "Flog, punish" , "Afflict" , "Whip; agent of suffering" , "Punish severely" .)