Prisoners' way to freedom.
In a stable prison with properly locked front-side doors, the only likely way for prisoners to escape is to dig tunnels from their cells (or use ropes to get over the walls if Escape Plans are enabled) to freedom.
- Prisoners can start digging a tunnel out of their Cell or Dormitory (not Holding Cells), using the fastest route to the outer-most wall beyond the prison area.
- A tool, such as a spoon, is required to dig. Many weapons (e.g. knives, forks) can also be used as a tool to dig tunnels.
- Prisoners will always start their tunnels from the toilet.
- They will only dig at night, and will set up a dummy (e.g. a paper mache decoy) to misrepresent that the prisoner is sleeping in bed.
- Prisoners will avoid walls when possible, since walls slow down digging time. Large Pipes will accelerate digging, so placing water pipes under walls is not recommended.
- Prisoners dig the shortest route to the building's exterior, then they continue digging until they meet the outermost fence or wall.
- If there's no external barrier, they will immediately dig upwards, exit the tunnel and attempt to escape.
- They aren't likely to dig under another building, unless there's no way to reach the final destination without doing so.
- Whilst they can dig through pipes, prisoners won't dig through or under natural Water, like ponds or lakes.
- Prisoners will cooperate by joining their tunnels and digging together.
- Each member of a dig team brings diminishing returns to the overall speed of digging, as they cannot dig all at once. It will take 4 prisoners to dig twice as fast as just 1 prisoner, and 11 prisoners to dig three times as fast as just 1 prisoner. They may, however, share any tools they have during the operation.
- When starting from individual cells, each inmate has to start his own tunnel, and they have to join later. When starting from a dormitory, multiple inmates can dig together from the beginning.
- Already exhausted prisoners will choose to sleep over digging.
- Prisoners need the clever trait to dig a tunnel.
- Prisoners who know that Guard Dogs are regularly passing over (and detecting) an in-progress tunnel will refrain from further digging attempts until they're sure they won't be detected. Setting up a patrol over a suspected tunnel area can delay escape attempts whilst searches are carried out.
- A guard searching the toilet may reveal the tunnel regardless of whether it's being actively dug at the time, but this is not guaranteed. Multiple searches of the toilet or even entire block may be required.
- A guard may detect the dummy by searching the prisoner while in bed and he may detect the tunnel if he is searching the cell. They may also notice the absence of prisoners during a Roll Call at night.
- A Guard Dog passing over a hidden tunnel outdoors will dig and scratch at the ground, temporarily generating an orange-brown indicator and a small flag. They can't reveal the entire tunnel (unless the player has chosen J. W. Periwinkle as a warden, who gives the dogs a 50% chance to fully uncover tunnels) but this can allow players to try to narrow down the tunnel's point of origin without needing to painstakingly search large areas.
- Guard Dogs will dig out prisoners if they are actively digging their tunnel right underneath the dog.
Prisoners caught digging will have the punishment for "Escape Attempt" automatically applied.
- An expensive Perimeter Wall will drastically slow down digging time, and if it can be afforded, it's highly recommended you surround your prison with it.
- Leave a hole in the Perimeter Wall (e.g. at the prison entrance) to lure prisoners to dig through it, but place a dog patrol above it.
- If this hole is too far away from their shortest way to the outer walls, prisoners will ignore this "honey pot", even with perimeter walls.
- Hire enough dogs to permanently have this patrol in action (two per patrol seem to work).
- Do not use large pipes near the outer prison wall. Make big pipes only lead from the cells to the prison center, not to the outer walls.
- If dog patrol leaves signs on the ground, search all toilets in the area.
- Easier to click: search cell block. But this takes more time for the guards and prisoners are more upset. There is a chance that tunnels will not be found this way though.
- Alternatively, click "Search for tunnels" on any toilet. This will search all toilets in the block for escape tunnels.
- Wait for the middle of the Sleep cycle, then search a suspicious block. Any active diggers will have dummies in place, which will be detected when searching the entire block - significantly increasing odds of finding any tunnels as well.
- Make extensive use of Metal Detectors near metallic contraband sources like Kitchens and Workshops, and in other high-traffic areas. Reducing prisoner access to Tools will make it that much harder for them to start digging in the first place. Wooden pickaxes from the workshop and ropes from the laundry are still a problem though...
Warning Signs of Digging Activity
- Prisoners engaged in digging will be tired the next day since they're not discharging their sleep need.
- If you have a Psychologist, check prisoners' sleep need just before dawn. If it's still high, they were likely digging during the night.
- If a prisoner has a high freedom need, they are much more likely to dig. Also the family need and the security need may be reasons to dig a tunnel.
- Prisoners will stop digging when a fight occurs nearby.
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