Outsiders in Surrey wrongly took bloody beating (7)

'bloody beating' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

'outsiders in surrey wrongly took' is the wordplay.
'outsiders in' says to hollow out the word (remove centre letters).
'wrongly took' becomes 'stole' (stealing is a kind of taking. I am not sure about the 'wrongly' bit.).
'surrey' with its centre removed is 'sy'.
'sy'+'stole'='SYSTOLE'

Can you help me to learn more?