The fridge option isn't that simple, though. It involves thinking that they're going to need to refrigerate the body. Then they have to empty out the fridge, maybe wondering what they're going to use to keep things cool in the meantime.
Then, they apparently got high for 3 days or something? It almost sounds like an attitude of , "now the job's done we can chill out" rather than "omg! what have we done, now we have a body to worry about!"
Maybe only a junkie could understand?
ETA, it could make sense to me if Rachelle acted alone and had planned it in advance. Then it would feel like "now the job's done and I need to get out of my head for a while before I actually dump the body". This feels like it might be consistent with the scenario I suggested earlier, that Rachelle did it alone and on purpose. Sorry to harp on that, I am completely open to all angles, I'm just trying to explore all the angles in my mind.