Continuity mistake: During the love scene Ethan has his left hand on Angelina's throat, but then it changes and it is his right hand.
Revealing mistake: Matt, the boy killed at the beginning, has very short hair. His dummy (the one hit by the white van) has much longer hair. (00:05:40)
Factual error: During Angelina and Ethan's "love" scene, they climb onto the table and smash what is quite obviously break away glass. No glass smashes that easily when merely touched.





Answer: Yes, he must do this to truly feel like the different person he is trying to be. Also, so the police won't suspect anything if his traits don't match his identity.