Going back to get the rent, are somehow trapped within it (2,7)

'going back to get' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.

'rent are somehow trapped within it' is the wordplay.
'are somehow' indicates anagramming the letters.
'trapped' becomes 'rea' (I can't justify this - if you can you should believe this answer much more).
'within' indicates putting letters inside.
'rent' anagrammed gives 'nret'.
'nret'+'rea'='nretrea'
'nretrea' going within 'it' is 'IN RETREAT'.

'the' acts as a link.

Can you help me to learn more?