So was that actually supposed to BE Andrea? I thought she shot herself?
She did shoot herself. She knows to shoot herself in the head. However, depending on where you put the guy, you could easily shoot yourself in the head and still be alive. One such example is one that my mother, who is an ER nurse, told me. There was this guy who killed his wife, shot her to death, and then turned the gun on himself, placing it to the side of his head and fired. Unfortunately, he had the gun too forward. So, instead of killing himself, he sent a bullet through the frontal lobe of his head. He pretty much lobotomized himself. I'm sure his plug was pulled years ago, but at the time, she told me he was pretty much a vegetable.
Now, people are going to say, "She could have put the gun under her chin and fired." That may very well be, however, if she did, there's still the chance she had the gun too far forward. In Season 4's episode "Live Bait," the Governor went into an apartment where Bill Jenkins, a legless veteran, used to live. The Governor found the zombified Bill, who apparently committed suicide by shooting himself in his head after climbing into the bathtub. However, he clearly had the gun too far forward (which resulted in his face being destroying his face, possibly lobotomizing himself, leaving his body to starve to death, die and eventually resurrect).
So, if it were suppose to be Andrea, it depends on where she put the gun to shoot herself, and if when she pulled the trigger, it was in a spot where the bullet could cause the correct amount of damage to the brain to keep from resurrecting. But since other sources have confirmed it was just a nod, there's no reason to think it is.