Maggie takes a ladder off the roof of the firetruck to help shade Eugene. The ladder was not on the roof during the events of Self-Help - it was hanging on the side of the truck.
After Beth is given the key to the drug locker by Dawn, Beth goes and asks Dr. Edwards what medication he would give to Carol to at least give her a fighting chance to recover. When he finally agrees he tells Beth that giving Carol 5 mg epinephrine IV drip will help lower her pulse and blood pressure. This is totally incorrect, epinephrine is a synthetic form of adrenaline, which acts as a stimulant, so it would make her blood pressure and pulse increase, not decrease. Plus the dose he tells Beth to give Carol would most likely kill her. The average dose of epinephrine used even for the most severe allergic reactions is 0.5 mg, so he told Beth to use a dose that is ten times what is normally used. Also Edwards tells Beth that the epinephrine is to be given as a drip, which means it is supposed to be injected into the IV bag so that it can be administered over time, however Beth injects the epinephrine directly into the IV line which would give her the entire dose at once and would almost certainly send Carol into cardiac arrest.
Beth was incorrectly filling syringes. When you insert the needle the vial can be left upright, however you are supposed to turn the vial upside down at about a 45 degree angle when filling the syringe, this helps prevent air from being drawn into the syringe.
When Abraham knocks the water bottle out of Rosita's hand and stands up as if to attack her, Maggie draws her revolver and tells him to "sit down or I'll put you down." When she draws her pistol we can clearly hear the sound of the hammer being cocked, but when she raises the gun the hammer is clearly not cocked, then her cocking the gun is shown with the same sound effect. This is actually a common mistake through out the series, the sound of a hammer being cocked on guns that either do not have an external hammer (like a Glock)or have one that is clearly not cocked.
When Rick is talking to the Sgt. while he was sitting. someone in the back can be seen overlooking through the window.
When Sasha is talking to the Sargent you can see someone walking in the background.
Carol is injured so badly that she is in a coma, and no one outside has a clue how badly she may be injured. Yet, Rick is determined to get her out of the hospital where they could only care for minor injuries.