The details of the electronic and solvent relaxation dynamics following two-photon excitation of an aqueous halide ion are studied via nonadiabatic quantum molecular dynamics simulation. It is found that the branching ratio at very early times (<50 fs) between two channels, a minor channel involving direct electron detachment to a spatially separated solvent void and a dominant channel characterized by delayed adiabatic detachment following a cascade through excited electronic states of the ion, is determined by the effect of solvent dynamics on the values of the ionic and void electronic energies, as well as the relative small matrix elements for tunneling into void states. Solvent dynamics is also found to be important in controlling the rate of electron transfer which leads to geminate recombination of proximal electron-halogen atom pairs. The sensitivity of this recombination rate to the relative energy levels of the unoccupied valence electron hole on the solvated halogen and that of the hydrated electron is indicated as the origin of the strong variation in the experimentally observed yield of diffusively free solvated electrons with halide species. In the case of delayed detachment, the symmetry characteristics of the one-electron state of the detaching electron are indicated as critical in facilitating the process; detachment is observed to occur only once the predominantly s-like lowest charge transfer to solvent (CTTS) ionic excited state is reached, and then the onset of separation is essentially immediate. A favorable solvent fluctuation in the vicinity of the site of detachment also precedes the onset of separation. Further experiments are suggested to clarify remaining differences between these conclusions and published interpretations of experimentally observed very early time relaxation dynamics of the CTTS states.