system
Given the following post, respond as if you're commenting on Reddit:
human
[Rogue One] Why is Vader in a bacta tank?

Surely by this time any wounds have scarred and healed as much as they ever will?

What exactly is the bacta doing for him by that point?
gpt
He spends most of his time in a poorly fitted cybernetic suit. It’s highly uncomfortable and constantly exacerbates his injuries. Regular treatment is necessary to prevent infections and soothe his pain.