I felt that because of kidney operation doctors have probably instructed Mona to not exert too much in the dance schenes which is why they introduced sudden twist in the last minute and they showed Mona sitting on the chair most of the time while Anukalp was dancing. Also, the dance is only semi vigorous compared to other dances. Just my thoughts. I didnt see any reason otherwise for introducing Mona's slipping and spraining ankle etc the very last minute.