Being a prison guard is definitely not dangerous. Go read the statistics. You might have one CO die per prison like every 7-8 years and thats nothing at all. Prisoners are more afraid of the COs than vice versa and they have good reason to be. They will lock you in a room and beat you unconscious as there is no law whatsoever in prison. Inmates can file grievances all they want but its their words against the gangs that run the prison (COs).

Its also not a hard job. All they do all day is count inmates and yell at them. They also love to provoke the inmates and get their jollies in the process.. real "stressful" job lol.
The real danger jobs are NYC taxi drivers, commerical fishermen, commercial loggers, farmers & ranchers, structural construction workers, sanitation workers, pilots, roofers, coal miners... seriously being a CO is not dangerous. Its more dangerous for them just driving to work everyday. Anyone who was a CO will obviously say its dangerous because of all the 0 tolerance bullshit. Only way to enforce all the petty rules they do is to scare the shit out of newbie CO's. But the ones who have been there for a long time will tell you straight up its a lot safer than you'd think.
The ones who say otherwise are liars.