Everybody hastened out of the plant (7)
I believe the answer is:
shallot
'the plant' is the definition.
The answer is an example.
'everybody hastened out' is the wordplay.
'everybody' becomes 'all' (all people).
'hastened' becomes 'shot' (shooting is a kind of hastening).
'out' is an insertion indicator.
'all' placed inside 'shot' is 'SHALLOT'.
'of' is the link.
(Other definitions for shallot that I've seen before include "found in the allotment" , "Type of onion" , "One may get into a stew" , "It resembles an onion" , "Species of onion" .)