Brutal interrogation after which you might call someone a doctor (5,6)
I believe the answer is:
third degree
'brutal interrogation' is the definition.
'third degree' can be an answer for 'interrogation' (third degree is a kind of interrogation). I am not certain of the 'brutal' bit.
'which you might call someone a doctor' is the wordplay.
I cannot really understand how this works, but
'call' could be 'hi' and 'hi' is found in the answer.
'doctor' could be 'dd' (Doctor of Divinity) and 'dd' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
'after' acts as a link.
Can you help me to learn more?
(Other definitions for third degree that I've seen before include "Demanding quiz" , "Extremely severe examination" , "Torture, especially to obtain information" , "Ruthless interrogation" , "What you may study for after master's" .)