Deliverance prompt, virtually all others going over the top (6)
I believe the answer is:
'deliverance' is the definition.
(I know that deliverance can be written as rescue)
'prompt virtually all others going over the top' is the wordplay.
'prompt' becomes 'cue' (cue can mean a prompt or signal).
'virtually' means to remove the last letter (the word is virtually but not totally complete).
'all others' becomes 'rest' (as in the rest of a group).
'going over the top' means one lot of letters go next to another (in a down clue, some letters go on top of others).
'rest' with its final letter removed is 'res'.
'cue' put after 'res' is 'RESCUE'.
(Other definitions for rescue that I've seen before include "Save from peril" , "Secure (anag) - release" , "Secure (anag) - deliverance" , "Free - recovery" , "delivery" .)