Alas, one can't buy insurance retroactively but I wonder if an outfit like GlobalRescue is a handy thing to sign up with. I think they get something upwards of USD2k/year for 'travelers insurance' that includes being plucked out of tight spots by a gang of ex-US Navy Seals they have on hand.
Re the topic, is the British Government involved/interested? I guess if the gang running the prison were unofficial terrorists instead of government terrorists there'd be some chance of a bit of a midnight arse-kicking.