Don't walk out - act as intermediary! (4,2)
I believe the answer is:
step in
'don't walk' is the definition.
The definition and answer can be both to do with social activities as well as being verbs in their base form.
Maybe there's an association between them I don't understand?
'out act as intermediary' is the wordplay.
I cannot really understand how this works, but
'act' could be 'step' (step is a kind of act) and 'step' is found within the answer.
'as' could be 'in' (I've seen this in other clues) and 'in' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for step in that I've seen before include "enter" , "Intervene dramatically, or at a senior level" , "Shoe with no fastenings" , "Type of garment" , "Substitute" .)