Gets worried about soldiers in part (7)
I believe the answer is:
segment
'part' is the definition.
(I know that segment is a kind of part)
'gets worried about soldiers' is the wordplay.
'worried' indicates an anagram (worry can mean to interfere with or disturb).
'about' means one lot of letters goes inside another.
'soldiers' becomes 'men' (men can mean a group of soldiers).
'gets' is an anagram of 'segt'.
'segt' placed around 'men' is 'SEGMENT'.
'in' acts as a link.
(Other definitions for segment that I've seen before include "Piece of an orange" , "One part of a whole" , "Part, piece" , "Part of, eg, an orange" , "split up" .)