:O Yooz got an evil hand, didn'tcha?
Iz trains on lowers floors too. If death shows up, leave and go back. It should reset the floor and he should be gone. It works with your party members stats as well. If your almost tired or out of SP or low on health, they'll refill once you go down and come back up.
Make sure your maxing your social links so you can make stronger Persona's in the Velvet room. It helps to skip out on Tartarus every once in a while. :3