During the fight the other night, Rachel decided it would be in her best interest to keep out of the conflict. Not that she didn't enjoy the tension, but it was easier to keep out of the way and not get involved. Though she could stand up to Sebastian easy enough, she was in no mood to get into arguments with him, mostly because Rachel didn't want to draw any attention to them. Fights between demons could get messy.
But at the same time, she didn't want to upset Kurt. Not just to keep up the pretext of being human, either. Despite her lack of soul and emotions, Rachel genuinely found herself enjoying the human boy's company. Her love of performance and interest in humanity, among other things, made her much different than most demons, so it was nice to find someone who shared her passions. It made her feel like maybe she belonged somewhere.
Hence why Rachel offered an olive branch, to make sure there were no hard feelings following her absence from the fight. She stopped at the coffee store, picking up both their coffees. She quickly checked to make sure Moulin Rouge was in her bag before starting for Kurt's dorm room. It was a good movie to continue with their musical marathon, especially with songs like Come What May and Elephant Love Medley. Stopping in front of the door, Rachel rapped quickly on the wood and called out "Special delivery!"