Just a quick render that looked cool..
It looks good. The terminator really looks like it's breathing. I'm still exploring what HitFilm can do so I'm curious how you used HitFilm for your video.
Pretty much self explanatory ...
Outside of hitfilm, i uploaded an OBJ file of the terminator to mixamo, and animated the breathing as a dae file, then in blender exported it as an alembic file, then imported it to hitfilm and animated the T pose 3d model of the terminator set to loop.
The backgrounds are from productioncrate and the music was created in FL studio 12 producer edition.