It follows immediately from the fact that Q(t) = (Q^\text{I}(t), Q^\text{II}(t)) satisfies the guiding equation that also the configuration Q^\text{I}(t) satisfies a guiding equation identical to the one presented in the formulation of the theory, with the universal wavefunction \psi replaced with the conditional wavefunction \psi^\text{I}.
\psi(t, q^\text{I} ,q^\text{II}) = \psi^\text{I}(t, q^\text{I}) \psi^\text{II}(t, q^\text{II}), .