Oral title: The Hunter's slingshot: Protostellar ejection from filaments in Orion Oral abstract: We compare 3 constituents of Orion A (gas, protostars, and pre-main-sequence stars), both morphologically and kinematically, to show the following. Essentially all protostars lie superposed on the Integral Shaped Filament (ISF), while almost all YSOs do not. The fact that protostars move <1 kms relative to the filaments while YSOs move several times faster implies that a “slingshot mechanism” may eject protostars from the dense filamentary cradle. The B-field strengths, compared with the gas mass distribution, indicates that magnetic instabilities may be propagating through the cloud.