The Immortal Egg
At the protected interior of the pocket dimension is Taylor’s immortal egg. The term “egg” describes its developmental function and the form it can project into ordinary space, although its central continuity-bearing structure remains beyond the normal portal boundary.
The immortal egg preserves several things that the exterior body is allowed to lose. Taylor’s genome provides the molecular instructions for rebuilding her tissues, while the protected niche also preserves enough positional and developmental information to begin placing those tissues correctly. A primitive form of the portal’s local control logic survives with it so that the first new cells are not being supplied from an unregulated dimensional opening. Under favorable circumstances, it also has access to enough stored matter and usable energy to reconstruct a developmentally young Taylor.
When Taylor is fully embodied, her tissues grow outward through the boundary into ordinary space. The visible body is therefore the ordinary-space manifestation supported by the protected dimensional core.
When the body is lost and Taylor retracts into egg form, only a small amount of living tissue needs to remain in the real world. Those cells sense broad environmental conditions, protect the opening, maintain the hatch, and provide a physical anchor.
The anchoring role becomes important because the immortal portion of the egg does not occupy ordinary space in the same way as the external shell. If Taylor withdrew every ordinary-space cell, her gravitational and physical coupling would become unusually weak. She might become partly intangible, only faintly visible, and prone to drifting relative to Earth as the planet rotates and moves through space.
The shell cells give the pocket dimension a physical proxy. They allow the egg to remain located in the environment, respond to pressure and contact, and maintain a stable point from which Taylor can later regrow.
The visible egg is therefore only the ordinary-space edge of the system. The exterior cells exist because that protected interior still needs a location, a sensor, and a controlled doorway into the world where Taylor intends to grow again.