“It was just Oliver walking through the house,” Polly Bennett, the film’s choreographer, told Vulture in December. “Then one day I was on set doing another piece of movement, and I popped in to see Emerald, and she said, ‘Oh, I’ve got an idea for the end. It involves a dance routine: He’s going to dance through the house to ‘Murder on the Dancefloor.””
Source: https://www.buzzfeed.com/josephlongo/murder-on-the-dancefloor-saltburn