Heater core delete??

You don't need to connect the core, connect the two going to the engine, or is that what you meant?

What I would do is get some scrap hose, attach, let the outlet down "safe" and rig something to blow gently in the other fitting, then change your drain hose to the opposite fitting and repeat. You can extract most of the coolant out of it so it won't drain anymore. Also, flush with water and drain, so any remaining drips will be simply "water"