Factual error: At CDC headquarters, Dr. Jenner shows Rick and the group an MRI of an infected patient's brain activity as they die and subsequently resurrect. The patient is shot at point-blank range as the barrel of the gun can be seen in the MRI. This is impossible. MRI machines are highly magnetic and the gun would have been ripped from Dr. Jenner's hands with such force that not only would he not have been able to shoot, the MRI machine would have been destroyed.
Continuity mistake: At the end of the previous episode, the sun was setting but wasn't set fully yet. There was still a decent amount of light left outside as the door to the CDC was opened. At the start of this episode, as they are entering, it's already pitch black outside.