<P> Filming took place at and around Loyola University in New Orleans, Louisiana, and it lasted 5 weeks . The scenes where Tree awakens in Carter's bed after her death were filmed back to back in a span of two days . The scene after Lori dies was supposed to be at the sorority house, but the filming permit was over before production was able to shoot there, forcing the location to be changed into a Los Angeles diner also featured in another Blumhouse production, Split . </P> <P> In the original ending of the film, Tree is taken to the hospital after her encounter with Lori . The doctor instructs her to stay away from pain medication for at least a day due to the extent of her injuries . After he leaves, a nurse comes in and tells Tree she is giving Tree something for the pain and Tree informs the nurse of the doctor's orders . The nurse reveals herself to be Dr. Butler's wife Stephanie, who murders Tree in revenge for the affair between her and Dr. Butler . </P> <P> This version was shown in the test screenings for the film, and was received negatively by the audience, forcing the writers to come up with the theatrical ending . Director Christopher Landon also revealed Lori and Dr. Butler were the killers in the rough drafts, which later inspired the idea of the poisoned cupcake . </P> <P> Happy Death Day grossed $55.7 million in the United States and Canada, and $59.5 million in other territories, for a worldwide total of $115.2 million, against a production budget of $4.8 million . </P>

Who played the murderer in happy death day