YOU SAID:

i have to do this or he's gonna kill me

INTO JAPANESE

これを行うに彼は私を殺すつもりか

BACK INTO ENGLISH

To do this he is going to kill me?

INTO JAPANESE

これをするために彼は私を殺すつもりですか？

BACK INTO ENGLISH

Is he going to kill me to do this?

INTO JAPANESE

彼はこれをするために私を殺すつもりですか？

BACK INTO ENGLISH

Is he going to kill me to do this?