Rules:
*You can teleport into and out of it at will
*It has a couple of plug sockets and can connect to internet from the region you teleported in from
*You can take objects and people with you
*As already stated, it is (3m)^3 (3m*3m*3m). The walls are plain plaster with a light in the middle of the ceiling. The pocket dimension is topologically toroidal, so if there weren’t walls and a ceiling/floor (which you can actually destroy) you would loop if you went more than 3m in any direction. Gravity, then, is artificial and can be altered to anywhere from 0 to 2g from a dial on the wall.
Edit: additional specifications
*You can only teleport out to where you teleported in from.
*Time proceeds at the same rate inside the pocket dimension
*There is an eject button for those inside to get out if something happens to you
Yes. People seem to think the bends always happens on exposure to weird pressures, but it just doesn’t. I guess they’re understandably imagining it’s the same as hot or cold.
Well, enough delta p is entirely capable of squishing an entire person through a thumb-sized hole, and while there’s no hole here I image there’d still be some sort of shock wave, and the air already in your lungs returning to normal volume suddenly would be uncomfortable. Don’t go too deep the first time, definitely ease into it.
Interestingly just 1 atm is fairly harmless. The first time someone got caught in a vacuum chamber they weren’t sure what they’d find, but the guy just got up and said his ears hurt.