In a panic once decided to yield (7)
I believe the answer is:
concede
'to yield' is the definition.
(I know that concede is a more specific form of the action give up)
'in a panic once decided' is the wordplay.
'in' says the answer is hidden in the clue.
'CONCEDE' can be found hidden inside 'panic once decided'.
(Other definitions for concede that I've seen before include "Admit; yield" , "Admit (defeat in match)" , "Admit something is true" , "Admit; surrender" , "Yield; grant" .)