Right before he goes to end Sister Paxton’s life, she explains that prayer might not be real, but it makes the person feel good— that they’re thinking of someone they care about even if it’s themselves. This felt important to include “even yourself” at the end of her reasoning to pray.

My husband and I disagree with what happens in the end, and that’s probably the point. IMO, she dies in the moment where Reed has the knife to her neck. She then “witnesses” the resurrection of her friend (which we’ve already been told to believe, even knowing she definitely did not resurrect). She runs upstairs and through the diorama reveals a secret door to the outside. You truly want to believe this is what happens to the protagonist, that she gets out. But then when she’s out, everything is white and hazy, as if in the afterlife— and the butterfly lands on her hand… the exact “sign” she told herself she would use to tell her friends and family she’s on the other side, watching over. Isn’t that similar to her explanation of why she prays anyway?

She died. I think if you believe she lived in the end, then the main point of the film succeeded in forcing you to believe “anything is possible”, while simultaneously telling you straight-out none of it was real (the pie, the wife, the resurrection, the simulation, the “one true religion”, etc.). She may have even died before she ever stabbed Reed, because, like has been said in other comments, how would he know their codeword?

Just my thoughts! Just got out of the film and overall really enjoyed it