some of the most dangerous inmates in the country. more than 600 condemned men await their execution dates here on death row. at california's san quentin state prison. in many of the prisons "lockup" crews have visited, death row is a quiet place where inmates are much more concerned with filing appeals than causing trouble. that's not the case here. [ alarm sounding ] >> me, myself, i consider every inmate in here a potential threat. >> our producer met two officers assigned to keep watch in the adjustment center, where san quentin's most violent death row inmates are housed. the daily grind here is bleak for both inmates and staff. >> mentality of most inmates in this unit is, i'm on death row, there's nothing you can do to me. if i assault you today, there's nothing you can do to me tomorrow. you can only kill me once.