It's still a wonderful sentiment. I know they'd be grateful for it.

[ She kneels down, closing her eyes and murmuring a few words. Words of goodbye, how much she had appreciated their friendship, and how she'll keep her promise. At least, she'll try her hardest to. They all deserve to leave here, alive. When she's done, she looks back up at Mettaton. ]

Where did you learn about it? A tradition from back home?