Hi! Good effort here but I honestly recommend you start out with a 2-story 2x3 Hlaalu house that fits one of the pre-existing exterior shells. There are a lot of dodgy choices in this cavern and it would probably be easier for you to start fresh with the Hlaalu house. But for the good of the order (and if you really want to fix this one up)

• Disconnect this from the exterior cell. Int developers don't work with exterior doormarkers (that's left to the people who merge the int with the current TR build), and it shows here because the doormarkers are set up wrong. The exterior door is supposed to teleport you to the interior (with that doormarker being in the interior), and the interior door is supposed to teleport you to the exterior (with that doormarker being in the exterior). Right now both of them teleport to the interior, so it's impossible to escape this cave in-game.
• The whole cave uses 2 different sets, the moldcave set and the mudcave set (distinguishable by the IDs and the different colors). Pick one, don't mix.
• In the first room, 2 rocks (in_mud_rock_07) are completely upside down, showing their missing face. This sort of thing appears in more places throughout the int.
• Remove the creatures, TR int devs don't normally add those (also, they're bled into the floor which is a no-no)
• The big final room is pretty lackluster, has a few huge upscaled rocks in the middle and some mudcrabs (which are inappropriate in interiors) but otherwise no detail.
• Add the prefix "TR_" to your cellname, it will make it much easier for reviewers and mergers to find.

If you fix these things then I will continue to review the showcase as normal, but I do strongly suggest changing it up and making a simple Hlaalu house, it's easier on both you and I and will teach you a lot for the upcoming Narsis interiors that will need to be made.