On topic of the Carbon Chamber scene, when Vader gets a face full...
What about adding some subtle movement to the steam from Vader's mask? As his mask functions as an intake and exhaust. We could see it either suck into his mask or exhale it out. Nothing major, but just noticable if you are looking for it.
it is something we saw in the ROTS when he finally puts on the mask for the first time, which was a cool effect that gave it more life.