After Johnny was mistakenly reported as killed, the next time we see him he is in a healing chamber, submerged in green-underlit translucent fluid, resting on form-fitting clear plastic supports. He breathes through a tube, and a pair of small robot arms work busily to regenerate the damaged tissue in his leg.
The main reason to discuss this chamber on a blog about interfaces is the material choice of the outside of the chamber. By being surrounded completely in a transparent material (glass? plexiglass? transparent aluminum?), it means that physicians can keep an eye on progress, and he can have visual interactions with visitors, as we see when Dizzy and Ace visit to share with him his mistaken death certificate (and for Dizzy to leave him a kiss.) Additionally it gives Johnny something to look at during the long hours of recuperation.
I’m not sure why the green light is necessary. The scene implies that it could serve some part in the healing process, but if not, I wonder if an amber light might signal a more human, nurturing warmth to Johnny and visitors. Narratively, you’d want to avoid anything too yellow or run the risk of the audience’s first interpretations drifting too far to the Andres-Serrano-esque.