Paul, for example, assuming duct is a means of egress (8)
I believe the answer is:
stairway
'is a means of egress' is the definition.
'paul for example assuming duct' is the wordplay.
'paul for example' becomes 'st' (abbreviation for saint).
'assuming' means one lot of letters go next to another.
'duct' becomes 'airway' (airway is a kind of duct).
'st'+'airway'='STAIRWAY'
(Other definitions for stairway that I've seen before include "- to Heaven, Led Zeppelin song" , "A flight of fixed indoor steps" .)