Why do quantum systems protect themselves from being driven too hard?

Pushing a quantum system too fast causes it to lose track of its own ground state — a phenomenon called non-adiabatic breakdown. This work reframes that breakdown using the geometry of quantum state space: how quickly a state moves through projective Hilbert space relative to the energy gap protecting it. The payoff is a single gauge-invariant number that predicts instability for any driven system, recovers the classic Kibble-Zurek freezing condition near phase transitions, and sets a hard lower bound on how fast a quantum gate can run without errors.