Continuity mistake: In the scene in which Abel is facing the gunmen with the shotgun, after Abel takes the gun away from the gunman and holds it up under his chin, the view changes from Abel's face to the gunman's face. When Abel's face is shown, the gunman's face is low, but when it switches to the gunman's face, you can note that his head is tilted up higher, and vice versa.
Plot hole: At the end, when Chris finds the informant's phone, he sees that there are 2 voicemail messages. Instead of listening to them, he calls the last number, which reveals Abel is responsible for the break-in when he answers and in turn reveals to Abel that Chris knows about the break-in. It would make more sense to just listen to the voicemails, as Chris became immediately suspicious when he saw them. Considering Chris called the last number, he must have known that the last number was also the person who left the voicemails. Very deliberately done to bring realizations between Chris and Abel for a climax.