"The Third Degree" refers to a long and detailed period of questioning, where pressure and intimidation may be used to get you to tell the truth. It does NOT normally imply torture. We use this idiom sarcastically when someone is asking us too many questions about something. If someone is asking you too many questions about something, you can say, "Stop giving me the third degree".

Third degree is used to represent bad-treatment / mistreatment Third degree interrogation means interrogation that is getting abusive or physical. Third degree treatment means when are treated really badly like in case you are a black guy and you walk into a bar full of white guys who consider themselves superior to black people the way they would behave to you is third degree treatment. (sorry no offense meant for anyone if you feel offended) Hence when it says stop torturing me it says that the person in concern was physically abused and he don't want to be treated that way. On personal note i think the translation done was poor.

It means interrogation, no longer asking. Like you are being interrogated by the police etc.

= (That is) an adequate amount (enough) of harsh interrogation (third degree).