The Penrose reduction theory is applied to a particle/detector interaction where the time that it takes for a particle capture (and reduction of the original state) is constrained by the Heisenberg uncertainty between time and energy . The usual interpretation of this equation is found to conflict with the Hamiltonian dynamics of the interaction. Another interpretation of this equation seems to solve that problem, but then another difficulty arises. We conclude that the Penrose theory cannot reflect the timing implicit in the Hamiltonian dynamics unless it can be amended to take account of the probability current flow between competing states. Key Words: decoherence, probability current, stochastic choice, wave collapse.