You have discovered a novel compound, which is an inhibitor of mitochondrial ATP synthesis.?

If electrons are piling up in the form of reduced NADH, it doesn't seem like the ETC is making much use of electrons, does it? Oxygen is the final electron acceptor in the ETC, so if electrons aren't being used, then oxygen probably isn't being used either. Stick that mythical probe in and see if this is the case.