When Carter arrives at the house where Naseri's daughter is being held he straps his phone to the outside of his left wrist but as he closes the car door the phone is no longer on his wrist & he can be seen holding it in his hand as he crosses the road (around 31/32 minutes) . Later, after he has subdued both the guards, the phone is seen strapped to the inside rather than the outside of his wrist (around 34 minutes).
In real life, the Pentagon is guarded by the Pentagon Force Protection Agency, which are civilian police officers. In the episode, it is shown as being guarded by Marine sentries.