It works! Armadillo did the important, expensive and meticulous scientific research:
During a tour of the shop I was explaining how our particular rocket engines worked. While doing this I discovered that an injector we had performed no less than a half dozen tests on was plumbed up backwards from what I was pointing out. This immediately explained much more to me than I would have cared to admit at the moment.
Suffice it to say that it is indeed possible to film cool an engine with LOX…