warned us, never get too comfortable around mark hinkston. >> we don't know from one day to the next what his demeanor is going to be. he has shown that he can become violent in an instant. >> i feel like i'm going to explode almost every day. it's really hard to keep my cool in this situation. >> hinkston had several violations leading up to his current eight-month-long segregation assignment. he attacked an inmate with a broomstick. threatened the lives of staff and made a shank. his latest violation was for stabbing another inmate with a pen. >> i ain't going to lie, he was stealing from me, i stabbed his ass as many times as i could. i will [ bleep ] him up with anything i get my hands on. i'm not just going fight you, i'm going try kill you if i can, man. >> hinkston was violent outside jail as well. he once served five years in prison for felonious assault and