Our psychological thriller shows that the character cares a lot about her appearance, this is shown when she re-applies her makeup. Furthermore, the character continues to do what she may do on a 'normal' day such as putting on shoes and fixing her hair and taking the medicine. This really represents her severe mental instability as there not only is there a dead person in the same house as her, they're in the same room as her. Normal people may feel guilty or even frightened for what they have done. But not this character as she is not in the right frame of mind and that is who she really is.
The act of 'normality' has been inspired by The Stepfather (2009) The character is carefully changing his appearance and then goes on to make breakfast. This all first tells us that he is all normal then knowing that he has just killed an entire family and they are laying on the floor in the same room as him shows the characters mind and inner self comes out more. This shocks the auidence as first we see a normal guy doing normal things then as the music changes we see bad things appear. Like so in our thriller movie her doing daily girly routine then we see hand layed on the floor all dead.