There's like another world hidden within a dome, in which somehow it's kids with magic (at least something good), who if they ever try to escape are chased by men who also have magic powers and are enthusiastic about violence and gore. Imagine being zapped a thousands times everywhere simultaneously by lightning. But the key idea here, everyone is immortal, they can be blasted to tiny pieces, turned into sludge but they're still alive and somehow if they do get dismembered they always reappear at the centre.
Anyway there looks to be three ways out, a water stream, a maglev, and maybe somehow through the air... Well okay, the water stream the kids don't realise has a very powerful suction machine that pulls in everything towards it, things that go in are macerated, usually the kids. (idk why it was so focused around kids). Turned into sludge and ejected into a box. Which is promptly returned by the men back to the main room. Oh BTW everything is designed to be extremely painful.
Then there's the train line, however touching it is extremely shocking, and somehow kids became ignorant of the pain, so I imagined myself getting across the line and it was attached to a building, so whilst having the shock I managed to get into this unknown building, where henchman just got some sort of extreme shocker and zapped me and sent me back. Then briefly saw these different colours of attachment things you see on electric pylons in life (the colourless ones, it doesn't make sense but it's a nightmare it don't have to), but essentially they were mentioning the kids are getting resistant to it so they're going to have to step it up to even greater shock amounts. Now I'm in a box and deported back to the room.

The room has awful upkeep and houses over a thousand kids. It's very plain and isn't interesting yet men guard it constantly.
Now kids are always trying to escape, because they were kidnapped from the real world, somehow each kid has a phone and the only number they can call is their mum, 911 simply reroutes to the men. Now the thing is, time doesn't appear to pass in this world, so the mums may quite literally be dead and long gone, yet somehow they hear their voices so it may be AI generated etc, fake voices. Urging the kids to get out.

Oh and this happens constantly on a loop. Kid tries to escape is tortured like crazy. Sent back in a box as a bunch of pieces.

The key themes is torture and kids it seems. Being kidnapped and constantly tortured if they try to escape.

The weird thing is, there's never any actual chance of escaping, the kids don't know that. Yet the place they're sent back to has nothing really there, there doesn't appear to be a purpose whatsoever.

Now the bit where I was in the nightmare, I was trying to escape, with magic I tried zapping the dudes, giving them small amounts of knock back so I could escape through the river. Yet I didn't know it was basically a macerator. The mind is basically reset every single time you get turned to pieces or tortured. Essentially incentiviisng you to escape constantly.
Oh BTW there's loads, and loads of blood and gore constantly. Imagine a saw movie, that's what it felt like when I was in the nightmare.