sit down. >> though returning to the cell block was difficult, talley told us it was also cathartic. >> yeah, i was down for awhile. but i'm not dead. they didn't kill me. i'm okay. emotionally, i'll heal. some day. and the sleepless nights, and the worry, and the wonder oh, my god, is this ever going to happen to me again. i've dealt with most of that. and it's -- it's really a hard thing. >> next, on "lockup: raw," an inmate turns violent against himself. >> [ bleep ] yeah! yeah! yeah! >> get down! yeah! >> [ bleep ] [ bleep ] >> violence inside america's prisons comes in many forms. at iowa state penitentiary, we found that the most brutal violence is sometimes against one's self. >> open 11. >> 22-year-old inmate caleb suffered severe burns over two-thirds of his body when the methamphetamine lab he was running exploded. when we interviewed him, he was also serving time for both sexual assault and for attacking a peace officer. >> i pushed everything to the limit because, as you can tell, i'm unstoppable. i think nothing can stop me. nothing will ever kill me. i thought i would d