Gail Simone and Ardian Syaf bring the first story arc featuring Mirror to a satisfying conclusion with issue #4 of
Batgirl! After 3 issues of telling us how smart Barbara(Batgirl)Gordon is, there's actually some evidence of that in how she sets up their final (hopefully) encounter.
Unfortunately, the elephant in the room for the entire series is back full force this issue with Barbara suffering 'survivor's guilt' dreams where she reflects a vocal readership faction's lament that she is no longer confined to a wheelchair. (I'm not quite sure that survivor's guilt works the way it's presented, but I'll go with the writer's choice here, as it addresses a fan contingent she wishes to appease. Ms. Simone has revealed in interviews how Babara regained her mobility, and there's a hint of that here, but not a full explanation (Not that any explanation is going to go over with certain fans, which is why if they were going to reboot the DCU, why not have this be a universe where 'The Killing Joke' did not happen?) While I have no problem with a crippled woman regaining the use of her legs in a universe where a previous Robin who was actually dead is running around fighting bad guys, I do think that the circumstances of Barbara's shooting should not be forgotten by the character, and Ms. Simone has failed to show that Barbara has learned anything from the incident. Here's Barbara opening the door to the Joker in 'The Killing Joke':

Now, you'd think that Barbara would be a bit security-conscious after that? At the very least, cautious about flinging the door open to any Tom, Dick (other than Grayson), or Joker! Much less move in with a roommate whom she has never met before! But, no! Instead, we get this:

I realize that it's difficult to build up a quirky supporting cast if your main character is a recluse, but there are ways to go about it that don't make the character appear to be an idiot. Ms. Simone almost got to the 'big reveal' about the roommate this issue, but it was interrupted. It'll probably be a sexuality thing which Ms. Simone obviously hopes will obscure the fact that she that shouldn't be there in the first place.As for the door opening, Ms. Simone spent 3 pages on Barbara's nightmare at the beginning of the issue which could just as easily been spent at the end showing what Babs was going through psychologically just to open the front door, allowing the writer to touch on all the points made in the nightmare sequence, while also having Babs act in a way that makes sense given her history.