Concealing a gun, he had stepped on it (8)
I believe the answer is:
hastened
'stepped on it' is the definition.
The definition and answer can be both to do with motion as well as being past participle verbs.
Maybe they are linked in a way I don't understand?
'concealing a gun he had' is the wordplay.
'concealing' is an insertion indicator.
'gun' becomes 'sten' (British sub-machine gun).
'he had' becomes 'he'd'.
'a'+'sten'='asten'
'asten' inserted into 'hed' is 'HASTENED'.
Can you help me to learn more?
(Other definitions for hastened that I've seen before include "Went quickly" , "Hurried or expedited" , "Rushed" , "Sped" .)