It's worth emphasising that the OME (the main engine) and the RCS (the attitude thrusters) both run on hydrazine fuel, but the OME also has a separate tank of o

It's worth emphasising that the OME (the main engine) and the RCS (the attitude thrusters) both run on hydrazine fuel, but the OME also has a separate tank of oxidant. So, the OME is a bipropellant engine, while the RCS is a monopropellant engine, which is why the OME is more efficient. (Aside: that's actually a really neat trick, and this is the first I've heard of it being used.) After the OME engine nozzle broke off and the engine became useless, the tank of oxidant became useless mass. (65kg.) So they dumped it overboard, simply venting it out the broken rocket nozzle. (Yes, the did point the vehicle in the right direction so that they could get some momentum change out of it.) Making that decision, to dump irreplaceable fuel overboard because of a conclusion you've reached by looking at some telemetry graphs, is one that I am very glad I wasn't the one to have to make.