Surveillance operation ditching Sierra or Escort (4,3)
I believe the answer is:
take out
'escort' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for take out that I've seen before include "Extract; kill" , "Remove; escort" , "Remove from within" , "Bump off" , "Kill (colloq.)" .)