In this work we use the all-order resummed solution of the BDMPS-Z spectrum to shed light on the dynamics that controls the in-medium radiation process for each kinematical regime. We find that multiple scatterings are essential to correctly describe the radiation process both in the low and mid-energy regime, while in the high-energy region one single hard scattering is enough. Furthermore, we compute the all-order spectrum when the medium is produced with a time delay with respect to the hard process in which the parent parton was created. The propagation of the hard parton through vacuum before the medium formation induces extra medium-induced radiation which might have impact on phenomenological analyses.