Just going to add my opinion onto this because I think my interpretation has been wrong up until this point as well. In my round today as the HoS we had a case where a vampire escaped from custody multiple times while they were being processed into perma (yeah yeah, we should have had blindfolds on hand so they couldn't glare, hindsight and all that, didn't realize we had none around until it was too late). But through this they escaped custody while being processed into perma. Captain ordered them executed for this and I oversaw the execution being carried out. I was boinked because they escaped but weren't actually in perma yet when they escaped so they said that this is not an escape from perma. The admin later said that it was justified in this case though. However from this I realized that the admin was interpreting "escaping perma" to refer to escaping the location and not the sentence. But up until this point I'd been interpreting it differently.
In the SoP itself it says "Any prisoners that escape Permanent Imprisonment or Exile may be detained, executed or killed on sight at the discretion of Security."
Permanent imprisonment to me sounds like the sentence and not the location. That would mean that escaping from custody if you've been sentenced to permanent imprisonment would fall under this, even if they haven't been put into the permanent prison itself. If they are sentenced to perma but are being brought to medbay for treatment and escape, this still sounds like an escape from permanent improsonment to me, even though they aren't in perma jail at the time.
If that's not the meaning then I think it should be reworded to say something along the lines of "ANy prisoners that escape from the perma prison" or something along those lines to make it clear that it's referring to the location would be better. The way it is right now sounds very much like it's referring to the sentence and not the location.
This is further supported by the fact that the line below, and 3 lines above are also referring to sentences and not locations. It says "Any prisoners that escape from an execution sentence are to be killed on sight". It does not say "Any prisoners that escape from he execution ROOM are to be killed on sight". To me it sounds like the intention of the permanent imprisonment one is the same.