You should be able to choose what you will get from the Twisting Corridors (Anima, Gear, Cosmetics or Soul Ash). Before getting in, you have to get a “key” from Ve’nari which will determine the kind of loot you are running for.
Lets say that you get the “Anima Collector” which, of course, will collect anima from all the enemies that you kill. It will also give you the option to turn “Lost Souls” into Anima. If you can’t finish the “run” you will lose 1/2 of what you collected.
If you want some gear you will need the “Anima Infusor” which will infuse a “blank Item” with power. It will give you the option to infuse Lost Souls into your item. This blank Item is a piece of gear previosly selected. It will be LVL 01 at the begining, and it will grow in power. At the 16th floor it should be around LVL 200, therefore those final floors are the really important ones. If you can’t finish the “run” you will get what you infused, lets say LVL 216.
If you want some mounts or transmogs you will need the “Anima Crystallizer” which will create an “Anima Crystal” that will be used as an opener (Didn’t want to say Key again) for some special kind of chests hidden in the corridors. It will also give you the option to absorb Lost Souls for your Anima Crystal. This Anima Crystal will grow and grow and will be consumed when used on a Chest. So you will have to decide between opening some small chests or a big one at the end, guarded by the final boss. The small ones could contain one piece of unique transmogs, therefore you will need several of them to complete a set; and the big one could contain mounts or pets.
Finally, if you want Soul Ash you will need the “Soul Ash Collector” which will work the same way than the “Anima Collector” does. It will give you the option to turn Lost Souls into Soul Ash. If you can’t finish the “run” you will loose 1/2 of what you collected.
At the end, even if you couldn’t finish the “run” you won’t feel like you just wasted your time, because you got some of what you wanted. Of course I wanted that 3000 Anima bunch, but this 1296 Anima bunch is great, and it’s way better than nothing. And it makes sence, all the Anima is in the Maw! Of course I wanted that LVL 233 Chest Plate, but this LVL 216 is nice. It’s OK I didn’t finish, finally I completed the most bad “axe” transmog.
I’m sorry for my bad English, I’m not a native speaker. Please let me know my mistakes so I can improve. Greetings from Mexico! (I hope Taliesin reads this… Hi Evi!)