In this article we reconsider the problem of the propagation of waves in a random medium in a kinetic regime. The final aim of this program would be the understanding of the conditions which allow to derive a kinetic or radiative transfer equation. Although it is not reached for the moment, accurate and somehow surprising number estimates in the Fock space setting, which happen to be propagated by the dynamics on macroscopic time scales, are obtained. Keel and Tao endpoint Strichartz estimates play a crucial role after being combined with a Cauchy-Kowalevski type argument. Although the whole article is focussed on the simplest case of Schrödinger waves in a gaussian random potential of which the translation into a QFT problem is straightforward, several intermediate results are written in a general setting in order to be applied to other similar problems.