I'm guessing there's a way to get things in if people can get in. I'll try and tell you what I find later.
i use the turret method to get in try looking straight down when spawning the item or merging them into the tube
i'm currently working on a map that incorporates this method, i just geomerged stuff in there such as a teleporter node and a couple of spawn points including a grav lift.
yeah i got in...turret in, change to monitor, float up and transform to person. I took pictures with mah new budah.
There is no way to spawn any size able item in there. The actual area with the flood in it is a kill zone, you die. You can only get in the little corner, the biggest thing you can spawn is a Fusion Coil. Also, the area with the flood is fake, you go through it.