Revealing mistake: When Robert Downey Jr. is taking Halle Berry's blood pressure, the needle doesn't move as he pumps the hand inflator.
Revealing mistake: When Halle Berry is speaking to her husband about Chloe, she mentions the medications she has given her. She pronounces Haldol like "Haddadol." As her character's a doctor, she would know the proper pronunciation of the medications. (00:06:15)
Revealing mistake: Rain doesn't fall in a circle pattern as seen, revealing the use of a rain maker.
Answer: The blood is not from Miranda; the drop of blood is a sign from the "dead girl" to tell Miranda that she should go to the place in the pic. Miranda goes the next day and that's how she finds her husband was a sadist.