Greene suggests to Weaver that they have Carter submit to a drug test, but Weaver says that Carter would test positive anyways because he is being prescribed an opioid for his back pain. The toxicology tests done at hospitals are able to distinguish between different kinds of a drug type, not just whether its an amphetamine or opioid but also which exact drug it is. Carter is being prescribed an oral opioid, likely hydrocodone or oxycodone, but is being accused of injecting fentanyl, which he is not being prescribed. An advanced toxicology panel can easily distinguish between the two, the test can show if he has just oxycodone in his system or both oxycodone and fentanyl, and it can even give an estimate of the dose taken and when it was taken.
When Carter injects the fentanyl, he pushes the plunger without first pulling it back to get a register and ensure the needle is in a vein. An experienced IV drug user - especially one who also is a physician - would never inject drugs in such a manner.
When Mark and Kerry are talking about Carter in one of the exam rooms, the door doesn't seal. The door is left ajar about 1 inch because it doesn't meet with the door jamb, even after they close it. It looks like the door is too small.
When Benton and Kovac are arguing, the sound of the helicopter's blades is heard, with the sound indicating that the blades are moving fast, but the shadow on Benton's shoulder shows that the blades are barely moving.
While in the lounge, while Malucci is pouring himself a cup of coffee and talking to Carter, Malucci's mouth doesn't move for about two seconds while his dialog is heard.
The police officer guarding the doctors at the helicopter evacuation has his finger on the trigger of his gun. Officers are trained never to put their fingers on the trigger unless they intend to fire the weapon.