Set off from Berkshire college in time (8)
I believe the answer is:
detonate
'set off' is the definition.
('detonate' can be a synonym of 'set off')
'berkshire college in time' is the wordplay.
'berkshire college' becomes 'eton' (I've seen this before).
'in' is an insertion indicator.
'time' becomes 'date' (date is a kind of time).
'eton' put within 'date' is 'DETONATE'.
'from' acts as a link.
(Other definitions for detonate that I've seen before include "let off" , "Cause to explode" , "Blow up, explode" , "Start 15 [EXPLOSION]" , "Set off explosive device" .)