Andrea. What a horrible person. She is so infuriating, it's ridiculous. She can't do a single thing properly! She can't kill him in his sleep but then comes back and FINALLY goes "he has to die." Of course, Milton stops her but...what he says makes sense. But then she finally leaves to the prison and surprisingly manages to escape the town. But of course she fucks up hiding out in an abandoned building because she knocks stuff over while creeping around. Of course. And when she DOES escape the governor again, she doesn't try to steal the car or slash the tires or anything to make it more difficult for him to get her if she happened to escape. And then gets captured. She has made mistake after mistake after mistake and nothing has really caught up with her. It's about time!
I've disliked her throughout season 3, and she has certainly made stupid decisions, and even the decisions that weren't stupid (from her perspective, given her knowledge and situation) were always grating. But this episode marked the turning point, of Andrea finally getting a little smarter and starting to do something, and overall actually doing a pretty awesome job of it. After all, how far is the prison from Woodbury? A dozen miles, at least. I'd be exhausted just from walking that distance, but she had to fight off Walkers, elude the Governor, and so on, so that in and of itself is an impressive accomplishment. And yeah I thought she should have slashed the tires of his car or sabotaged it in some other way, but I think she came out the building on another side and didn't have time to run all the way around to get to it. Perhaps it was a very large building, or walkers were closing in, or she correctly assumed that the governor wasn't about to be killed, even if it was by a whole pack of walkers. So while things like her extremely loud sneaking were annoying, the rest of the episode was such an improvement over her other actions over the course of this season, that I'm more than willing to overlook them.
Also, I just want to add that as soon as I saw the Governor preparing his torture room, I thought how it really wouldn't be fair for Michonne to end up there and suffer at his hands, and that I really don't want that to happen to her. Andrea, on the other hand... A lot of viewers either hate her or just dislike her now, so a bit of torture at the hands of the villain followed by some vengeance is just what her character needed for redemption.