For one, abandon the "Forcefield" as a security door. Subsequent failure of power, the field dissipates. My guess Brig is largely for insubordinate officers/crew, hence letting them stay onboard during evacuation/ship abandonment is tant amount to cruel/unusual. Like what happened in jails in Hurricane Katrina.
In the Voyager episode "Repentence" They go thru the work off fabricating 8 prison cells of Tritanium bulkheads, but use forcefields which fail.
Even the most recent episode of ST: Prodigy, Gwyn escapes from her cell in an instant power fails.
Better strategy is Manual doors like real prisons. Modern control prisons are abandoning classic "Bars" in favor of solid doors.
In trek's case Transparent aluminum windows, several centimeters thick is more than adequate.
Fits scifi theme of transparent prison cells
"Avengers"
James Bond
"Silence of the lambs"
To be as escape proof as possible said walls will contain No electric work, electronics or wiring.
- Light provided by Fiber optics
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Federation prisons, would be much like the one on Elba II.
Planet's hostile environment makes no need for conventional security, even if you escape where you gonna go?
Another idea is building a habitable dome over a Class D planetoid