There are 8 squilly respawn points into the cell. Above is a combined pearl glitching, upwards mining, and squilly obstruction detector. On all other sides there are only mining detectors. Crawl mode respawning is prevented by a 1-high backup cell below the prisoner's respawn point filled with lava where they can stand up and die.
More Security
The prison is surrounded by a circle of detecting outer bans that lead to the suicide, around many layers of anvil redstone grid. Above the prison is a sculk-based mining detector. Below is a combined pearl glitch, squilly, and explosion detector. Chorus fruit will not arrive and nether portals don't generate above the nether roof. Since the prison is in the nether spawnchunks, chunkskipping, tile tick suppression, light suppression, squilly respawn issues, and chunk abuse are all impossible. Logging out inside the prison during construction is made less likely because of its fast build time, and it can be placed at many locations to make logging out before more difficult as well. If prisoner respawn glowstone gets low, the prison cell will be temporarily banned until a guard can refill the glowstone.
