Let’s take a look at some of the other worst offenders:
At the beginning of the game, Harley Quinn seems to have gotten access to the security forcefield control room, and has a pass to enable/disable them. We’ll gloss over the fact that Arkham was willing to employ someone who was obviously already unstable enough to allow herself to be lured by the Joker into villain-dom, and focus on how she managed to get into the control room… Did she break in? If Harley Quinn, with her red and blue Basque and chalk white face makeup, was somehow able to evade security, it’s a pretty sad state of affairs. Also, why does her security pass still work? I’m pretty sure most high security prisons collect those and deactivate them once you become an inmate.
Leading on from this, why do they let Batman walk right up to the Intensive Treatment rooms? Yes, he’s Batman, and is unlikely to break anyone out of Arkham, but is it hospital policy to allow heavily armed, masked men walk the corridors?
Batman? Upset the inmates? How very dare you...
Of course, once you’re barred from proceeding any further (you’ll “upset the inmates”, apparently… where obviously a chemically-scarred, maniacal, psychotic mass-murderer won’t), that’s where things go wrong. As soon as Joker is able to get somewhere he’ll cause some damage, he is being attended by a single unarmed guard and an orderly. They even take him out of the restraints they had him in to take him down to the treatment rooms!
How did the Riddler hide all these trophies around the place? Most of them are in places even Batman struggles to get to, so Riddler must have been crawling around ventilation shafts for months. As a side issue, did no-one realise Batman had a Batcave hidden in the foundations? How did he even build it?** Who knows what else is lurking underneath the mansions.
A more appropriate level of security
With all of these flaws, it’s no wonder people are constantly breaking out. That said, when the founder of the Asylum’s idea of treatment is fatal electrocution, it’s not hard to see why the place doesn’t have a roaring trade in rehabilitation (and why so many people are keen to leave).
*Beyond the obvious ‘revolving door’ policy on sentencing, of course.
**Actually, this has always bothered me about Batman. Where does he get his labour? Do Bruce and Albert do all the heavy construction work in the Batcave themselves, or do they have a very discrete building contractor?