Immediately after touching from behind, the Reverend quietly disappeared (2,6)

I believe the answer is:

no sooner

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'the reverend quietly disappeared' is the definition.
I know nothing about this answer so I can't tell whether this works.

'immediately after touching from behind' is the wordplay.
'immediately' becomes 'sooner' (I can't justify this - if you can you should give a lot more credence to this answer).
'after' means one lot of letters go next to another.
'touching' becomes 'on'.
'from behind' says the letters should be written in reverse.
'on' reversed gives 'no'.
'sooner' put after 'no' is 'NO SOONER'.

Can you help me to learn more?

I've seen this clue in The Hindu.

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