Departure from a line in the reduced text (4)

I believe the answer is:
exit
'departure' is the definition.
(synonyms)
'a line in the reduced text' is the wordplay.
'a line' becomes 'i' (I can't explain this - if you can you should believe this answer much more).
'in' means one lot of letters goes inside another.
'the reduced' means to remove the first letter.
'text' with its initial letter taken away is 'ext'.
'i' put within 'ext' is 'EXIT'.
'from' is the link.
Can you help me to learn more?
(Other definitions for exit that I've seen before include "[DOOR] ?" , "Player's departure" , "Actor's departure" , "Escape route?" , "Withdrawal" .)
