Crossword Genius

At prison was treated badly, but got through it (10)

Ross

I believe the answer is:

penetrated

I'm a little stuck... Click here to teach me more about this clue!

'at prison was treated badly but got through it' is the definition.
I can't tell whether this definition defines the answer.

'prison was treated badly but got through it' is the wordplay.
I cannot quite see how this works, but
'prison' could be 'pen' (both can mean an enclosure) and 'pen' is located in the answer.
an anagram of 'treated' is 'etrated' which is present in the answer.
No letters remain.
This explanation may well be incorrect...

Can you help me to learn more?

I've seen this clue in the Evening Standard.
Want a hint initially instead of a full solution? Install my app