Hasanovic

I've wanted to create a Halo cosplay for 3D print. Fortunately, I could download that helmet. I cutted the vision and the bottom of the helmet (blender). The problem I have, right now, is that cura prints inside that helmet (yellow parts). I tried to cut that helmet in two parts but that ain't work :(. Can someone help me how to let those holes be holes? Here is my file: Helm-ganz.stl