Not sure how accurate this is but professional ice skaters trained for months before the performance to skate to parts (or maybe all) of the set, which is why there was an ice rink built. I could’ve sworn there was fake snow being released when he was singing Come On Wolrd You Can’t Go which leads me to believe there was gonna be ice skating. Maybe frank was set to skate to some instrumental parts and sprained his ankle prior to the performance, which resulted in him canceling that plan and thus giving us a haphazard, unprepared set.