Expert pursuing soldiers in danger (6)
I believe the answer is:
menace
'danger' is the definition.
(menace is a kind of danger)
'expert pursuing soldiers' is the wordplay.
'expert' becomes 'ace' (ace is a kind of expert).
'pursuing' means one lot of letters go next to another.
'soldiers' becomes 'men' (I've seen this before).
'ace' after 'men' is 'MENACE'.
'in' is the link.
(Other definitions for menace that I've seen before include "peril" , "Threat, danger" , "Serious threat" , "ominous atmosphere" , "serious nuisance" .)