Not prepared to go out as one press chief enters (8)
I believe the answer is:
unedited
'not prepared to go out' is the definition.
(not ready to be published)
'one press chief enters' is the wordplay.
'one' becomes 'united' (synonyms).
'press chief' becomes 'ed' (editor).
'enters' indicates putting letters inside.
'united' enclosing 'ed' is 'UNEDITED'.
'as' is the link.
(Other definitions for unedited that I've seen before include "In the original version" , "Left as seen" , "as it was first presented?" , "As written, without correction" , "unchanged" .)