There's a review on Vulture that addresses a lot of things, among them the phone call Walt made to Skyler (and for god's sakes it's not "Skylar" already). It gives a pretty compelling argument for the fact that this was done specifically to protect her and absolve her from wrong-doing in the eyes of the feds. It wasn't exactly a performance, as we've seen happen with this character -- Walt didn't sit down and rehearse this before calling her, as he did earlier in the episode -- but it was more of a split personality type of thing:
The gist: I do not believe, as some are already speculating, that when Walter spews all that venom at Skyler while the feds and Marie and Walt, Jr. listen in, that it’s “really” Walt pretending to be Heisenberg — i.e. that it’s all some big fake-out. I think that’s Heisenberg speaking. But I think it’s Heisenberg speaking on Walt’s behalf. I think this might be one of those rare moments on Breaking Bad — the rescue of Jesse at the end of “Full Measures” being another — where Walter wants to do something that Walter is just not capable of doing, something chaotic and frightening but ultimately good, and Heisenberg steps up to make it happen.
I find it fascinating how divided the fans are on the character of Walter White. For some people, he crossed the line when he allowed Jane to die. For others, it was when he uttered the words, "Stay out of my territory." Others when he killed Gus, or poisoned Brock, or killed Mike, or any number of heinous acts he's done. And some are still rooting for him. Imagine if, at the beginning of the series, we knew everything about him that we know now, the despicable acts that mild-mannered Walter White will commit. Nope, we could all relate to him -- who hasn't had a shitty boss, who doesn't make enough money to cover their bills, who doesn't have something in their past that rankles them still? I think it's that relatability in the beginning of the series that pulled us in as far as the character is concerned, and at every horrible step of the way, we've managed to forgive him and justify his actions until the point where we have to get off the Walter White/Heisenberg love train and accept that he's become an irredeemable monster.
I also have never understood the fan vitriol that gets sent Skyler's way; she's not exactly blameless in any of this but I have always seen her as a woman caught in a tidal wave, grasping for anything that will keep her from being swept out to sea. The review also had this to say:
I love how this scene is comprised mainly of the sorts of things that Skyler haters have been saying on message boards and in the comments sections of recaps since Breaking Bad debuted in 2008. It’s as if the show is using these same sentiments to rebut them: Walter’s voice is deeper and more monstrous, his tone more venomously cruel, than in any other exchange between him and Skyler. It takes the vicarious pleasure that some viewers take in the sight of milquetoast Walter White becoming The One Who Knocks and curdles it, makes it ugly, poisonous — as if the show is saying, “This is what you wanted, isn’t it? Here you go. Choke on it.”
Anyway, it's a good review, so here's the link:
http://www.vulture.com/2013/09/breaking-bad-recap-season-5-hank-dies-ozymandias.html