You can break INTO prison.
Not sure if anyone posted about it before, I just found it cool, so I wanted to share it.
I followed this video to break out of the prison using parkour, and that got me wondering whether I can break back in - and what happens if I do get back in.
Answer: Yes, you can get back inside. It's finicky but possible.
As for what's inside after you get back in, that depends on how you left.
Case 1: You broke out via parkour like in the video. Even though you get the achievement for breaking out (if this was the first time), the game doesn't actually treat escape as an escape. Once you break back in, prison life continues like you never even left, nothing changes. (Also: If you happen to die outside of the prison after parkouring out, you'll be teleported to the dock, not inside the prison.)
Case 2: You got out the intended way. Zero will wear their regular clothes, your team will be visible, but you won't be able to switch to anyone besides Zero. (So no cheesing your way back in with Nanally.)
Once you get back inside, a very different prison greets you. Most NPC-s are gone, only some "environmental" ones remain inside their cells and in the infirmary. Patrolling guards stay on the inside, the interact bubble hovers by them (part of their model/assets?), but you cannot actually interact with them.
Items can still be picked up and stolen - the "stealing" minigame still plays out, the camera pans out, but there is no NPC to "catch you" in the act. All doors (besides infirmary) are open, you can go anywhere you can physically reach. Except your cell, for some reason.
Interestingly enough any escape routes you've opened remain open. Which means that you can technically "break out" of prison, even though you're not even in prison anymore. NPC-s are gone, but the lights scanning the area remain, and if you step into them, you will get "caught" and sent back into your cell. (And this is the only way I found to re-enter your cell after "breaking in".) Your sentence gets extended, but the next day will always be "release day", and will land you in the dock area upon waking up.
Once you reach the exit of the escape route, the game won't treat it as you successfully escaping - after exiting through the sewers I got a warning about it being the entrance to the prison. Which makes sense, because I wasn't in prison at the time I "broke out", so the game treated me as if I was free and trying to enter, even though I was actually leaving.
(Fun detail: When you approach the sewer entrance from the outside, it forces you to turn back and leave. Apparently this is not programmed to make you go AWAY from the entrance, but to make you turn around and run the OPPOSITE direction, the direction you came from. In my case, this meant making me run toward the entrance and towards the prison, because that's where I came from.)
All in all, breaking back into prison doesn't achieve anything, but it's still cool to take a look at how it's made, and check out the various areas freely!
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Update: After logging out (still on the island, but technically having already broken out of prison the intended way), and logging back in the next day, the game treats me as a prisoner again. The rest of the team is gone, Zero is back in prison uniform, BUT the prison yard remains empty. (That was only the case after successfully breaking out - when I parkoured my way out, the prison remained populated with NPCs.) Seems like the game can't quite decide whether I'm in prison or not. Will update with what happens if I manage to get back inside.
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Update 2: I did manage to get back in, and it was interesting. It looks like I really was in a "limbo" between free and captive; the prison itself worked like I was free (meaning most NPC-s are gone, Zero's cell is locked, etc.), but Zero/my team worked like I was captive. My HP also got set to full, even though I wasn't on full HP when I escaped properly and logged out yesterday.
Interestingly enough, this time there was one NPC I could interact with! Squid Ball was present and I could actually trade with him. Though, nobody else was there. Squid Ball also wasn't present when I broke in previously as a "free" person. Not sure what made him appear this time.
Collectibles have also fully respawned. Items I've previously stolen in my last break-in did not respawn.
NPC prisoners and guards are absent, but Squid Ball remains this time, for for some reason.
The sewer entrance I've unlocked during my prison gameplay remained open still as well - and I could escape, once again. This time when I exited the sewers, the warning message did not trigger and Zero wasn't forced to turn around, so my "escape" was actually treated as an "escape"...? Sort of. It did not unlock the sewers as a means of escaping, like it would if you escaped through it normally.
I did not test what happens if I get caught in this "limbo" state. Maybe I'll try another time, or perhaps someone else can pick up from here and see what other shenanigans we could get into after breaking into prison. =)
No warning or forced retreat this time; just a fade to black + teleport to the entrance.
I took the boat back to the city and after reaching the shore. My team was restored AND Zero got back to the HP he was originally at before I got put into the "limbo" state - which further proves to me that yes, the game did indeed register me as a prisoner in some way, and put me in a half-prisoner, half-free state.
I also took the chance to capture some more footage of the whole thing. Perhaps I'll cut it and upload it later, just to show the place (in this state) in detail. If I do that, I'll also include the way into the prison.
Overall, there's absolutely no practical reason to break back into prison, but it was a pretty fun adventure. NTE is great for messing around like this. I can't wait to see what other places might be reachable similarly!
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Small update: I beat up some people for lunch and money and got thrown in prison again. The sewers escape route was re-sealed now; previously it remained open, no matter how many times I "escaped", "got released", broke out, got caught, and even escaped legitimately. Even after logging out and back in the next day, it remained open.
This makes me think that the state of the prison only resets on your next admission into prison.
Not sure what can be done with this information, but I wanted to add it in case it ends up being useful. =)