if you accidentally leave the Z-level, it's easy getting back for me if mining didn't do anything
>find the AI teleporter room
>go out the door then go straight down (unless if you have glass or a shard)
>leave the z-level, go down a bit, if there's nothing, go back up and go back down
>until you find mcpubbies or russian station
>go back up and go up a little when you leave the z-level. if you don't find the teleporter, just keep exiting and coming back
>go back in and build the teleporter, which if you don't know, wrench, circuit board, screwdriver, cables, 2 sheets of glass (which you can get by welding the shards), screwdriver, done
>tele back
use this to find the spaced captain or something and be a hero. then get a promotion and get all-access, go to chemistry and make POO SMOKE