  We consider gravitational massive scalar-scalar scattering from unitarity and
demonstrate how intermediate soft graviton behavior and the concept of
extracting classical physics from localization of integrands on velocity cuts
devise an efficient extraction scheme for computing the classical
post-Minkowskian radial action perturbatively. We demonstrate the computational
efficiency by deriving the scattering amplitudes in the probe regime to the
fifth post-Minkowskian order in arbitrary dimensions.
