Land on empty crate and flinch (5)
I believe the answer is:
wince
'flinch' is the definition.
(I know that flinch can be written as wince)
'land on empty crate' is the wordplay.
'land' becomes 'win' (both can mean to secure).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'empty' suggests removing the centre.
'crate' with its centre taken out is 'ce'.
'win'+'ce'='WINCE'
'and' is the link.
(Other definitions for wince that I've seen before include "React involuntarily from pain or embarrassment" , "Make face showing pain" , "Start back in pain" , "Look disgusted" , "pained" .)