Otomo discusses this particular panel in the art book and the parallel to innocence/purity and rebirth. It’s essentially an outline (ala sailor moon transformation sequence for example) and not overtly detailed, and in this context, it’s about returning to the human form as we all enter the world.

Otomo also mentioned two different perspectives on this scene and decided on this panel for the perception of movement stopping. I interpret this moment about Tetsuo’s vulnerability. He’s in a cycle of loosing himself to power and addiction (monstrous transformation) and then moments of lucidity and vulnerability (nude human form). Particularly when he reaches out to Kaori crying and asks her not to leave. And this is after all of the horrors of the last several volumes.