Quantum Artificial Intelligence
Despite being a full-pledged Chimera, Xi Shi didn't have that much of a tolerance for pain.
In fact, Xi Shi would have passed out the moment I finish flaying her lovely arm if it wasn't for all those mircomachines floating around in her bloodstream, keeping her conscious.
The same micromachines that are inhibiting her regenerative ability.
Xi Shi obviously didn't know that fact. She assumes that her inability to heal herself is due to my rather unexplainable power.
It is unexplainable, at least from a biological standpoint, and even with near unlimited funding by their respective government, those organization behind these Hybrids would never reach the same level of technology as Hydra, let alone me.
Hydra didn't have access to antigravity technology yet, and Hydra will not have it until all the plans for colonizing all the planets in the solar system come to fruition.