We review the current state of the art of techniques in general relativity involving null and/or distributional sources of stress-energy, with an emphasis on the study of gravitational shockwaves. We then propose a series of unsolved problems in which these techniques can be applied to uncover novel features of causal structure. In particular, we demonstrate methods in which the gravitational field due to quantum fluctuations can be modeled under the assumption that gravity is coherent over causal diamonds. The first example studied is the decay of a particle with mass $M$ into two counter-propagating null point particles. The resulting spherical shockwave is shown to produce displacement and velocity memory on a system of spherically arranged, synchronized clocks. We then consider quantum superpositions of decay axes and demonstrate that fluctuations of time shifts measured on the system of clocks should scale like $\langle \delta \tau^2\rangle/\tau^2\sim t_p/ \tau$ in the limit of Planck mass particles. The second problem studied is the gravitational effect of a ``bubble model'' representing the effective stress-energy of a pion. It is shown that such a model produces a mean secular outward acceleration of nearby test bodies that is consistent with the relative acceleration of bodies due to the cosmological constant.